Initial parametric Feather case generator

.bundle/config

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+---
+BUNDLE_PATH: "vendor/bundle"
+

.gitignore

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+# Generated CAD and preview output
+/build/
+*.stl
+*.3mf
+*.amf
+*.off
+*.png
+/cases/*/exports/
+/cases/*/previews/
+/cases/*/history/
+/cases/*/.rebuild-*/
+/cases/.*
+
+# Local Ruby dependencies and test output
+/vendor/bundle/
+/coverage/
+/tmp/
+*.log
+
+# Python/Blender caches and crash dumps
+__pycache__/
+*.pyc
+core
+core.*
+
+# Local environment and editor files
+.env
+.env.*
+.DS_Store
+*.swp
+*.swo
+*~
+/.idea/
+/.vscode/
+/.ruby-lsp/

Gemfile

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+source "https://rubygems.org"
+
+gem "highline", "~> 3.1"
+
+group :development do
+  gem "minitest", "~> 5.22"
+end

Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    highline (3.1.2)
+      reline
+    io-console (0.8.2)
+    minitest (5.27.0)
+    reline (0.6.3)
+      io-console (~> 0.5)
+
+PLATFORMS
+  x86_64-linux-gnu
+
+DEPENDENCIES
+  highline (~> 3.1)
+  minitest (~> 5.22)
+
+BUNDLED WITH
+   2.4.20

README.md

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+# Parametric Feather Case
+
+An OpenSCAD enclosure generator for the Adafruit ESP32 Feather V2, stacked
+FeatherWings, an optional protected 18650 pack, and an optional 1/4-20 camera
+mount. It produces a body, removable lid, OLED button plungers, and fit
+calibration coupons.
+
+## Interactive Ruby wizard
+
+The HighLine wizard asks the project-specific questions, saves the answers in
+YAML, and builds a self-contained case directory with OpenSCAD source, STL
+and/or 3MF geometry, and rendered previews.
+
+Install the Ruby dependency into this repository:
+
+```bash
+bundle install
+```
+
+Then run:
+
+```bash
+bundle exec bin/feather-case
+```
+
+The menu can create a case, reopen one for dimensional tuning after a test
+print, or rebuild an existing case. Generated definitions live under
+`cases/<name>/`; exports, previews, revision history, and `vendor/bundle` are
+ignored by Git.
+
+OpenSCAD and Blender must be available on `PATH`. On Ubuntu:
+
+```bash
+sudo apt-get install openscad blender
+```
+
+Set `OPENSCAD=/path/to/openscad` or `BLENDER=/path/to/blender` when either
+program is installed elsewhere. The wizard checks both tools before replacing
+an existing package.
+
+Each generated directory contains a dependency-free `build.rb`. After copying
+that directory to another Ubuntu machine, run `ruby build.rb` to reproduce its
+exports and previews. The saved generator source is used by default so a
+fine-tuning pass cannot silently pick up later geometry changes.
+
+OpenSCAD's 3MF output contains portable model geometry. It does not contain a
+Bambu printer, filament, plate, or process profile; select those settings after
+opening the files in Bambu Studio.
+
+The design targets support-free FDM printing with a 0.6 mm nozzle. PLA and PETG
+are suitable for general use; ASA is the preferred starting material for
+outdoor exposure. The enclosure is not weather-sealed.
+
+## Reference geometry
+
+All dimensions are millimetres. Board coordinates come from Adafruit's source
+files:
+
+- [ESP32 Feather V2 PCB](https://github.com/adafruit/Adafruit-ESP32-Feather-V2-PCB)
+- [ESP32 Feather V2 CAD](https://github.com/adafruit/Adafruit_CAD_Parts/tree/main/5400%20ESP32%20Feather%20V2)
+- [128x64 OLED FeatherWing PCB](https://github.com/adafruit/Adafruit-OLED-FeatherWing-PCB)
+- [128x64 OLED FeatherWing CAD](https://github.com/adafruit/Adafruit_CAD_Parts/tree/main/4650%20OLED%20FeatherWing)
+- [Adafruit 69 x 18 mm protected 18650 pack](https://www.adafruit.com/product/1781)
+
+The board origin is its USB edge at `(0, 0)`. The case uses X from the USB wall
+toward the rear, Y from the plain side toward the battery/JST side, and Z up
+from the exterior bottom.
+
+## Generate parts
+
+Open [feather_case.scad](feather_case.scad) in OpenSCAD and use the Customizer,
+or override values from the command line:
+
+```bash
+# Generic one-Wing case
+openscad -o body.stl -D 'part="body"' feather_case.scad
+openscad -o lid.stl -D 'part="lid"' feather_case.scad
+
+# Three-Wing GPS case with battery and camera mount
+openscad -o gps-body.stl \
+  -D 'part="body"' \
+  -D 'top_profile="gps"' \
+  -D 'wing_count=3' \
+  -D 'battery_enabled=true' \
+  -D 'tripod_insert_enabled=true' \
+  feather_case.scad
+openscad -o gps-lid.stl \
+  -D 'part="lid"' \
+  -D 'top_profile="gps"' \
+  -D 'wing_count=3' \
+  -D 'battery_enabled=true' \
+  -D 'tripod_insert_enabled=true' \
+  feather_case.scad
+
+# 128x64 OLED lid and all four captive buttons
+openscad -o oled-lid.stl \
+  -D 'part="lid"' \
+  -D 'top_profile="oled128x64"' \
+  -D 'button_reset=true' \
+  feather_case.scad
+openscad -o oled-buttons.stl \
+  -D 'part="buttons"' \
+  -D 'top_profile="oled128x64"' \
+  -D 'button_reset=true' \
+  feather_case.scad
+```
+
+The standard stack height is `wing_count * wing_pitch`. Set
+`stack_height_override` to the measured distance from the Feather PCB top to
+the top FeatherWing PCB when using unusual headers. It takes precedence over
+the computed height.
+
+## Custom wire egress
+
+`extra_cutouts` accepts any number of entries:
+
+```openscad
+// [face, shape, u, z, width, height, radius]
+extra_cutouts = [
+    ["left",  "circle",    35, 10, 8,  8, 4],
+    ["rear",  "roundrect", 20, 12, 14, 7, 2],
+    ["right", "slot",      28, 15, 18, 5, 2.5]
+];
+```
+
+Faces are `front`, `rear`, `left`, and `right`. For front/rear faces, `u` is
+the global Y coordinate; for left/right faces it is global X. The Z value is
+the opening centre. Shapes are `circle`, `rect`, `roundrect`, and `slot`.
+Cutouts that enter the floor or lid-lip keepout raise an assertion instead of
+silently weakening those features.
+
+## Calibration
+
+Heat-set insert holes vary significantly by insert brand, filament, nozzle,
+temperature, and printer calibration. Treat the supplied values as starting
+points.
+
+1. Export and print `part="insert_coupon"` in the intended material.
+2. Test both M2.5 and 1/4-20 inserts in the five stepped holes.
+3. Set `m25_insert_hole_diameter` and `tripod_insert_hole_diameter` to the best
+   coupon values.
+4. Print `part="switch_coupon"` and choose the best hole for the actual DMWD
+   switch batch.
+5. Print `part="fit_coupon"` and tune `fit_clearance` before committing to the
+   complete lid and body.
+
+For ASA, tune dimensional compensation with coupons rather than applying an
+assumed global shrink percentage. Start with four or more walls, good chamber
+temperature control, and the same extrusion settings intended for the case.
+
+## Assembly
+
+1. Heat-set the optional 1/4-20 insert from inside the case. Its threaded
+   opening faces the exterior bottom.
+2. Heat-set four M2.5 inserts into the board standoffs.
+3. Fasten the ESP32 Feather V2, then install the stacking headers and Wings.
+4. For battery builds, place the protected 69 x 18 mm pack in the cradle, route
+   its lead through the partition notch, and mount the latching switch in the
+   battery-side wall.
+5. Heat-set the four lid inserts downward into the corner bosses.
+6. For OLED builds, insert each enabled printed plunger through the lid from
+   the inside. The elongated flange stays in the internal recess.
+7. Engage the lid rim and fasten four standard M2.5 socket-head screws into the
+   2.5 mm-deep counterbores.
+
+Confirm the USB plug, switch, battery, insert, and lid fits without force before
+leaving a lithium-ion battery installed. The battery cradle is intended for
+Adafruit's protected pack, not an unprotected loose cell.

bin/feather-case

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require_relative "../lib/feather_case_wizard"
+
+exit FeatherCaseWizard::CLI.new.run
+

cases/gps/README.md

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+# GPS
+
+Generated by the Feather Case Wizard.
+
+- Top profile: `gps`
+- FeatherWings: 1
+- Battery compartment: yes
+- 1/4-20 insert: yes
+- Approximate exterior: 93.9 × 57.3 × 38.6 mm
+- Formats: 3mf
+- Parts: `body`, `lid`
+- Custom cutouts: 0
+
+Run `ruby build.rb` in this directory to regenerate exports and previews.
+OpenSCAD and Blender must be installed. Set `OPENSCAD` or `BLENDER` to
+override their executable paths.
+
+To open the saved Customizer values manually:
+
+```bash
+openscad -p parameters.json -P gps source/feather_case.scad
+```
+
+The 3MF files contain portable geometry only. Choose printer, filament,
+plate, and slicing settings in Bambu Studio.

cases/gps/build.rb

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "fileutils"
+require "json"
+require "open3"
+require "pathname"
+require "tmpdir"
+require "yaml"
+
+ROOT = Pathname(__dir__).expand_path
+
+def executable(env_name, command)
+  override = ENV[env_name]
+  return File.expand_path(override) if override && File.executable?(override)
+
+  ENV.fetch("PATH", "").split(File::PATH_SEPARATOR).each do |directory|
+    candidate = File.join(directory, command)
+    return candidate if File.file?(candidate) && File.executable?(candidate)
+  end
+  nil
+end
+
+def literal(value)
+  case value
+  when String then JSON.generate(value)
+  when TrueClass then "true"
+  when FalseClass then "false"
+  when Numeric then value.to_s
+  when Array then "[#{value.map { |item| literal(item) }.join(",")}]"
+  else raise "Cannot convert #{value.inspect} to OpenSCAD"
+  end
+end
+
+def run!(*command, env: {})
+  stdout, stderr, status = Open3.capture3(env, *command)
+  return if status.success?
+
+  warn [stdout, stderr].reject(&:empty?).join("\n")
+  raise "Command failed (#{status.exitstatus}): #{command.first}"
+end
+
+config = YAML.safe_load_file(ROOT.join("case.yml"), permitted_classes: [],
+                             permitted_symbols: [], aliases: false)
+openscad = executable("OPENSCAD", "openscad")
+blender = executable("BLENDER", "blender")
+abort "OpenSCAD not found; install it or set OPENSCAD" unless openscad
+abort "Blender not found; install it or set BLENDER" unless blender
+
+parameters = config.fetch("parameters").merge(
+  "extra_cutouts" => config.fetch("resolved").fetch("extra_cutouts")
+)
+parts = %w[body lid] + config.fetch("outputs").fetch("coupons")
+buttons = %w[button_a button_b button_c button_reset]
+if parameters["top_profile"] == "oled128x64" &&
+   buttons.any? { |name| parameters[name] }
+  parts << "buttons"
+end
+
+stage = Pathname(Dir.mktmpdir(".rebuild-", ROOT.to_s))
+begin
+  exports = stage.join("exports")
+  previews = stage.join("previews")
+  scratch = stage.join("meshes")
+  FileUtils.mkdir_p([exports, previews, scratch])
+  model = ROOT.join("source/feather_case.scad")
+  renderer = ROOT.join("source/render_stl_previews.py")
+
+  export = lambda do |output, part, overrides = {}|
+    values = parameters.merge(overrides).merge("part" => part)
+    command = [openscad, "-o", output.to_s]
+    values.each { |name, value| command.concat(["-D", "#{name}=#{literal(value)}"]) }
+    run!(*command, model.to_s)
+  end
+
+  config.fetch("outputs").fetch("formats").each do |format|
+    directory = exports.join(format)
+    FileUtils.mkdir_p(directory)
+    parts.each do |part|
+      puts "Exporting #{part}.#{format}…"
+      export.call(directory.join("#{part}.#{format}"), part)
+    end
+  end
+
+  assembly = scratch.join("assembly.stl")
+  puts "Preparing assembly preview…"
+  export.call(assembly, "assembly",
+              "exploded_view" => config.fetch("outputs").fetch("assembly_exploded_view"),
+              "show_references" => false)
+  render_env = {"DISPLAY" => nil, "WAYLAND_DISPLAY" => nil}
+  run!(blender, "--background", "-noaudio", "--python", renderer.to_s, "--",
+       assembly.to_s, previews.to_s, "assembly", env: render_env)
+  parts.each do |part|
+    puts "Rendering #{part} preview…"
+    mesh = scratch.join("#{part}.stl")
+    export.call(mesh, part) unless mesh.file?
+    run!(blender, "--background", "-noaudio", "--python", renderer.to_s, "--",
+         mesh.to_s, previews.to_s, part, "iso", env: render_env)
+  end
+
+  backup = ROOT.join(".build-old-#{Process.pid}")
+  FileUtils.mkdir_p(backup)
+  %w[exports previews].each do |name|
+    current = ROOT.join(name)
+    FileUtils.mv(current, backup.join(name)) if current.exist?
+  end
+  begin
+    FileUtils.mv(exports, ROOT.join("exports"))
+    FileUtils.mv(previews, ROOT.join("previews"))
+    FileUtils.rm_rf(backup)
+  rescue StandardError
+    FileUtils.rm_rf(ROOT.join("exports"))
+    FileUtils.rm_rf(ROOT.join("previews"))
+    %w[exports previews].each do |name|
+      saved = backup.join(name)
+      FileUtils.mv(saved, ROOT.join(name)) if saved.exist?
+    end
+    raise
+  end
+  puts "Rebuilt #{ROOT}"
+ensure
+  FileUtils.rm_rf(stage)
+end

cases/gps/case.yml

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+---
+schema_version: 1
+name: GPS
+slug: gps
+generator:
+  sha256: a265164909faa0c364792224601af36381744a129b7cd7cbd6b6293815953f63
+  created_with: feather-case-wizard
+parameters:
+  top_profile: gps
+  wing_count: 1
+  wing_pitch: 11.0
+  stack_height_override: 0.0
+  generic_component_height: 3.0
+  generic_top_gap: 2.0
+  gps_antenna_height: 4.0
+  gps_top_gap: 5.0
+  oled_component_height: 2.4
+  oled_face_gap: 0.8
+  button_a: true
+  button_b: true
+  button_c: true
+  button_reset: false
+  button_projection: 1.5
+  button_cap_size:
+  - 5.0
+  - 3.2
+  button_flange_size:
+  - 6.6
+  - 3.6
+  button_flange_thickness: 0.9
+  button_travel: 0.5
+  button_contact_extension: 0.7
+  battery_enabled: true
+  battery_length: 69.0
+  battery_diameter: 18.0
+  battery_radial_clearance: 0.6
+  battery_end_clearance: 1.0
+  switch_hole_diameter: 12.0
+  switch_hole_compensation: 0.3
+  switch_cap_diameter: 8.0
+  switch_flange_diameter: 16.2
+  switch_body_length: 24.0
+  switch_body_diameter: 12.0
+  switch_wire_allowance: 3.0
+  tripod_insert_enabled: true
+  tripod_insert_length: 6.4
+  tripod_insert_hole_diameter: 8.8
+  tripod_thread_clearance_diameter: 6.8
+  tripod_boss_diameter: 14.0
+  m25_insert_length: 4.0
+  m25_insert_hole_diameter: 3.7
+  m25_screw_clearance: 2.8
+  m25_boss_diameter: 7.0
+  insert_entry_chamfer: 0.6
+  insert_melt_relief: 0.8
+  wall_thickness: 2.4
+  floor_thickness: 2.4
+  lid_thickness: 3.2
+  corner_radius: 4.0
+  board_bottom_clearance: 5.4
+  board_side_clearance: 7.0
+  board_rear_clearance: 4.0
+  usb_board_wall_gap: 1.2
+  lid_lip_depth: 2.4
+  lid_lip_thickness: 1.2
+  fit_clearance: 0.35
+  hole_compensation: 0.2
+  lid_screw_head_diameter: 5.2
+  lid_screw_head_height: 2.5
+  usb_opening_width: 12.5
+  usb_opening_height: 7.0
+  usb_opening_radius: 1.5
+  usb_vertical_offset: 0.0
+cutouts: []
+outputs:
+  formats:
+  - 3mf
+  coupons: []
+  assembly_exploded_view: 8
+resolved:
+  extra_cutouts: []

cases/gps/parameters.json

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+{
+  "parameterSets": {
+    "gps": {
+      "top_profile": "\"gps\"",
+      "wing_count": "1",
+      "wing_pitch": "11.0",
+      "stack_height_override": "0.0",
+      "generic_component_height": "3.0",
+      "generic_top_gap": "2.0",
+      "gps_antenna_height": "4.0",
+      "gps_top_gap": "5.0",
+      "oled_component_height": "2.4",
+      "oled_face_gap": "0.8",
+      "button_a": "true",
+      "button_b": "true",
+      "button_c": "true",
+      "button_reset": "false",
+      "button_projection": "1.5",
+      "button_cap_size": "[5.0,3.2]",
+      "button_flange_size": "[6.6,3.6]",
+      "button_flange_thickness": "0.9",
+      "button_travel": "0.5",
+      "button_contact_extension": "0.7",
+      "battery_enabled": "true",
+      "battery_length": "69.0",
+      "battery_diameter": "18.0",
+      "battery_radial_clearance": "0.6",
+      "battery_end_clearance": "1.0",
+      "switch_hole_diameter": "12.0",
+      "switch_hole_compensation": "0.3",
+      "switch_cap_diameter": "8.0",
+      "switch_flange_diameter": "16.2",
+      "switch_body_length": "24.0",
+      "switch_body_diameter": "12.0",
+      "switch_wire_allowance": "3.0",
+      "tripod_insert_enabled": "true",
+      "tripod_insert_length": "6.4",
+      "tripod_insert_hole_diameter": "8.8",
+      "tripod_thread_clearance_diameter": "6.8",
+      "tripod_boss_diameter": "14.0",
+      "m25_insert_length": "4.0",
+      "m25_insert_hole_diameter": "3.7",
+      "m25_screw_clearance": "2.8",
+      "m25_boss_diameter": "7.0",
+      "insert_entry_chamfer": "0.6",
+      "insert_melt_relief": "0.8",
+      "wall_thickness": "2.4",
+      "floor_thickness": "2.4",
+      "lid_thickness": "3.2",
+      "corner_radius": "4.0",
+      "board_bottom_clearance": "5.4",
+      "board_side_clearance": "7.0",
+      "board_rear_clearance": "4.0",
+      "usb_board_wall_gap": "1.2",
+      "lid_lip_depth": "2.4",
+      "lid_lip_thickness": "1.2",
+      "fit_clearance": "0.35",
+      "hole_compensation": "0.2",
+      "lid_screw_head_diameter": "5.2",
+      "lid_screw_head_height": "2.5",
+      "usb_opening_width": "12.5",
+      "usb_opening_height": "7.0",
+      "usb_opening_radius": "1.5",
+      "usb_vertical_offset": "0.0"
+    }
+  },
+  "fileFormatVersion": "1"
+}

cases/gps/source/feather_case.scad

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+/*
+ * Parametric enclosure for the Adafruit ESP32 Feather V2 and FeatherWings.
+ *
+ * Coordinate system:
+ *   X: USB-C wall (0) toward the rear of the case
+ *   Y: non-battery side (0) toward the battery/JST side
+ *   Z: outside bottom (0) upward
+ *
+ * Board coordinates are derived from Adafruit's Eagle PCB files:
+ *   https://github.com/adafruit/Adafruit-ESP32-Feather-V2-PCB
+ *   https://github.com/adafruit/Adafruit-OLED-FeatherWing-PCB
+ */
+
+/* [Output] */
+part = "assembly"; // [assembly,body,lid,buttons,insert_coupon,switch_coupon,fit_coupon]
+exploded_view = 8; // [0:1:20]
+show_references = true;
+
+/* [Stack] */
+top_profile = "generic"; // [generic,gps,oled128x64]
+wing_count = 1; // [1:1:8]
+wing_pitch = 11; // [7:0.1:16]
+stack_height_override = 0; // [0:0.1:100]
+generic_component_height = 3; // [0:0.1:30]
+generic_top_gap = 2; // [0.5:0.1:10]
+gps_antenna_height = 4;
+gps_top_gap = 5;
+oled_component_height = 2.4;
+oled_face_gap = 0.8;
+
+/* [OLED controls] */
+button_a = true;
+button_b = true;
+button_c = true;
+button_reset = false;
+button_projection = 1.5; // [0.5:0.1:3]
+button_cap_size = [5, 3.2];
+button_flange_size = [6.6, 3.6];
+button_flange_thickness = 0.9;
+button_travel = 0.5;
+button_contact_extension = 0.7;
+
+/* [Battery and switch] */
+battery_enabled = false;
+battery_length = 69;
+battery_diameter = 18;
+battery_radial_clearance = 0.6;
+battery_end_clearance = 1;
+switch_hole_diameter = 12;
+switch_hole_compensation = 0.3;
+switch_cap_diameter = 8;
+switch_flange_diameter = 16.2;
+switch_body_length = 24;
+switch_body_diameter = 12;
+switch_wire_allowance = 3;
+
+/* [Tripod mount] */
+tripod_insert_enabled = false;
+tripod_insert_length = 6.4;
+tripod_insert_hole_diameter = 8.8;
+tripod_thread_clearance_diameter = 6.8;
+tripod_boss_diameter = 14;
+
+/* [M2.5 inserts] */
+m25_insert_length = 4;
+m25_insert_hole_diameter = 3.7;
+m25_screw_clearance = 2.8;
+m25_boss_diameter = 7;
+insert_entry_chamfer = 0.6;
+insert_melt_relief = 0.8;
+
+/* [Shell and fit] */
+wall_thickness = 2.4;
+floor_thickness = 2.4;
+lid_thickness = 3.2;
+corner_radius = 4;
+board_bottom_clearance = 5.4;
+board_side_clearance = 7;
+board_rear_clearance = 4;
+usb_board_wall_gap = 1.2;
+lid_lip_depth = 2.4;
+lid_lip_thickness = 1.2;
+fit_clearance = 0.35;
+hole_compensation = 0.2;
+lid_screw_head_diameter = 5.2;
+lid_screw_head_height = 2.5;
+
+/* [USB-C opening] */
+usb_opening_width = 12.5;
+usb_opening_height = 7;
+usb_opening_radius = 1.5;
+usb_vertical_offset = 0;
+
+/* [Custom wall cutouts] */
+// Entry format: [face, shape, u, z, width, height, radius]
+// face: front, rear, left, right. u is Y on front/rear and X on left/right.
+// shape: circle, rect, roundrect, slot. Circle uses width as its diameter.
+extra_cutouts = [];
+
+/* [Calibration] */
+coupon_steps = [-0.3, -0.15, 0, 0.15, 0.3];
+
+$fn = $preview ? 36 : 72;
+eps = 0.02;
+
+// Adafruit Feather mechanical reference, millimetres.
+feather_length = 50.8;
+feather_width = 22.86;
+board_thickness = 1.6;
+mount_x = [2.54, 48.26];
+mount_y = [2.54, 20.32];
+usb_center_y = 11.43;
+
+// Official 128x64 OLED FeatherWing geometry in Feather-board coordinates.
+oled_visible_min = [11.42, 3.78];
+oled_visible_size = [30, 15.3];
+oled_button_a_xy = [4.318, 15.875];
+oled_button_b_xy = [4.318, 11.43];
+oled_button_c_xy = [4.318, 6.985];
+oled_button_reset_xy = [7.366, 20.828];
+
+effective_floor = tripod_insert_enabled
+    ? max(floor_thickness, tripod_insert_length + insert_melt_relief + 1.2)
+    : floor_thickness;
+effective_board_clearance = max(
+    board_bottom_clearance,
+    m25_insert_length + insert_melt_relief + 0.6
+);
+
+board_origin_x = wall_thickness + usb_board_wall_gap;
+board_origin_y = wall_thickness + board_side_clearance;
+board_bottom_z = effective_floor + effective_board_clearance;
+board_top_z = board_bottom_z + board_thickness;
+
+computed_top_pcb_z = board_top_z + wing_count * wing_pitch;
+top_pcb_z = stack_height_override > 0
+    ? board_top_z + stack_height_override
+    : computed_top_pcb_z;
+profile_component_height =
+    top_profile == "gps" ? gps_antenna_height :
+    top_profile == "oled128x64" ? oled_component_height :
+    generic_component_height;
+profile_top_gap =
+    top_profile == "gps" ? gps_top_gap :
+    top_profile == "oled128x64" ? oled_face_gap :
+    generic_top_gap;
+
+partition_y = board_origin_y + feather_width + 1;
+battery_center_y = partition_y + wall_thickness + battery_radial_clearance
+    + battery_diameter / 2;
+battery_start_x = board_origin_x + battery_end_clearance;
+battery_end_x = battery_start_x + battery_length;
+switch_center_x = battery_end_x + max(
+    switch_body_diameter / 2 + 0.8,
+    switch_flange_diameter / 2 + 0.5
+);
+
+case_length_plain = board_origin_x + feather_length
+    + board_rear_clearance + wall_thickness;
+case_length_battery = switch_center_x + switch_flange_diameter / 2
+    + 1.2 + wall_thickness;
+case_length = battery_enabled ? max(case_length_plain, case_length_battery)
+    : case_length_plain;
+
+case_width_plain = board_origin_y + feather_width
+    + board_side_clearance + wall_thickness;
+case_width_battery = battery_center_y + battery_diameter / 2
+    + battery_radial_clearance + wall_thickness;
+case_width = battery_enabled ? max(case_width_plain, case_width_battery)
+    : case_width_plain;
+
+battery_center_z = effective_floor + battery_radial_clearance
+    + battery_diameter / 2;
+switch_center_z = max(
+    effective_floor + switch_flange_diameter / 2 + 1,
+    battery_center_z
+);
+electronics_ceiling_z = top_pcb_z + profile_component_height + profile_top_gap;
+battery_ceiling_z = battery_enabled
+    ? max(
+        battery_center_z + battery_diameter / 2 + battery_radial_clearance,
+        switch_center_z + switch_flange_diameter / 2 + 1
+    )
+    : 0;
+body_height = max(electronics_ceiling_z, battery_ceiling_z);
+
+lid_boss_r = m25_boss_diameter / 2;
+lid_boss_wall_overlap = 0.6;
+lid_boss_xy = [
+    [
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap,
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap
+    ],
+    [
+        case_length - wall_thickness - lid_boss_r + lid_boss_wall_overlap,
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap
+    ],
+    [
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap,
+        case_width - wall_thickness - lid_boss_r + lid_boss_wall_overlap
+    ],
+    [
+        case_length - wall_thickness - lid_boss_r + lid_boss_wall_overlap,
+        case_width - wall_thickness - lid_boss_r + lid_boss_wall_overlap
+    ]
+];
+
+assert(wing_count >= 1, "wing_count must be at least one");
+assert(top_profile == "generic" || top_profile == "gps"
+    || top_profile == "oled128x64", "Unsupported top_profile");
+assert(wall_thickness >= 1.2, "wall_thickness is too small for 0.6 mm FDM");
+assert(lid_lip_thickness >= 1.2, "lid lip needs at least two 0.6 mm lines");
+assert(m25_boss_diameter > m25_insert_hole_diameter + 2,
+    "M2.5 boss does not have enough radial material");
+assert(!tripod_insert_enabled
+    || tripod_boss_diameter > tripod_insert_hole_diameter + 3,
+    "Tripod insert boss does not have enough radial material");
+
+function clamp(v, lo, hi) = min(max(v, lo), hi);
+
+module rounded_rect_2d(size, radius) {
+    r = clamp(radius, 0.01, min(size[0], size[1]) / 2 - 0.01);
+    hull() {
+        for (x = [r, size[0] - r], y = [r, size[1] - r])
+            translate([x, y]) circle(r = r);
+    }
+}
+
+module centered_rounded_rect_2d(size, radius) {
+    translate([-size[0] / 2, -size[1] / 2])
+        rounded_rect_2d(size, radius);
+}
+
+module centered_rounded_prism(size, height, radius) {
+    linear_extrude(height = height)
+        centered_rounded_rect_2d(size, radius);
+}
+
+module rounded_box(size, radius) {
+    linear_extrude(height = size[2])
+        rounded_rect_2d([size[0], size[1]], radius);
+}
+
+module insert_pocket(diameter, depth, entry_z, downward = true) {
+    bore_d = diameter + hole_compensation;
+    if (downward) {
+        translate([0, 0, entry_z - depth])
+            cylinder(h = depth + eps, d = bore_d);
+        translate([0, 0, entry_z - insert_entry_chamfer])
+            cylinder(
+                h = insert_entry_chamfer + eps,
+                d1 = bore_d,
+                d2 = bore_d + 2 * insert_entry_chamfer
+            );
+    } else {
+        translate([0, 0, entry_z - eps])
+            cylinder(h = depth + eps, d = bore_d);
+        translate([0, 0, entry_z - eps])
+            cylinder(
+                h = insert_entry_chamfer + eps,
+                d1 = bore_d + 2 * insert_entry_chamfer,
+                d2 = bore_d
+            );
+    }
+}
+
+module face_rounded_cutout(face, u, z, width, height, radius) {
+    r = clamp(radius, 0.01, min(width, height) / 2);
+    depth = wall_thickness + 2 * eps;
+    if (face == "front" || face == "rear") {
+        x0 = face == "front" ? -eps : case_length - wall_thickness - eps;
+        hull()
+            for (yy = [u - width / 2 + r, u + width / 2 - r],
+                 zz = [z - height / 2 + r, z + height / 2 - r])
+                translate([x0, yy, zz])
+                    rotate([0, 90, 0]) cylinder(h = depth, r = r);
+    } else if (face == "left" || face == "right") {
+        y0 = face == "left" ? -eps : case_width - wall_thickness - eps;
+        hull()
+            for (xx = [u - width / 2 + r, u + width / 2 - r],
+                 zz = [z - height / 2 + r, z + height / 2 - r])
+                translate([xx, y0, zz])
+                    rotate([-90, 0, 0]) cylinder(h = depth, r = r);
+    }
+}
+
+module face_circle_cutout(face, u, z, diameter) {
+    depth = wall_thickness + 2 * eps;
+    if (face == "front")
+        translate([-eps, u, z])
+            rotate([0, 90, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "rear")
+        translate([case_length - wall_thickness - eps, u, z])
+            rotate([0, 90, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "left")
+        translate([u, -eps, z])
+            rotate([-90, 0, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "right")
+        translate([u, case_width - wall_thickness - eps, z])
+            rotate([-90, 0, 0]) cylinder(h = depth, d = diameter);
+}
+
+module custom_wall_cutout(entry) {
+    face = entry[0];
+    shape = entry[1];
+    u = entry[2];
+    z = entry[3];
+    width = entry[4];
+    height = len(entry) > 5 ? entry[5] : width;
+    radius = len(entry) > 6 ? entry[6] : min(width, height) / 2;
+    assert(face == "front" || face == "rear"
+        || face == "left" || face == "right", "Invalid cutout face");
+    assert(shape == "circle" || shape == "rect"
+        || shape == "roundrect" || shape == "slot", "Invalid cutout shape");
+    assert(z - height / 2 >= effective_floor,
+        "Cutout intersects the floor");
+    assert(z + height / 2 <= body_height - lid_lip_depth,
+        "Cutout intersects the lid locating lip");
+    assert(
+        (face == "front" || face == "rear")
+            ? u - width / 2 >= 0 && u + width / 2 <= case_width
+            : u - width / 2 >= 0 && u + width / 2 <= case_length,
+        "Cutout extends beyond its wall"
+    );
+
+    if (shape == "circle")
+        face_circle_cutout(face, u, z, width);
+    else
+        face_rounded_cutout(
+            face, u, z, width, height,
+            shape == "rect" ? 0.02 :
+            shape == "slot" ? min(width, height) / 2 : radius
+        );
+}
+
+module board_standoffs() {
+    for (mx = mount_x, my = mount_y)
+        translate([
+            board_origin_x + mx,
+            board_origin_y + my,
+            effective_floor - eps
+        ])
+            cylinder(
+                h = effective_board_clearance + eps,
+                d = m25_boss_diameter
+            );
+}
+
+module lid_bosses() {
+    for (p = lid_boss_xy)
+        translate([p[0], p[1], effective_floor - eps])
+            cylinder(
+                h = body_height - effective_floor + eps,
+                d = m25_boss_diameter
+            );
+}
+
+module battery_cradle() {
+    partition_height = min(
+        body_height - lid_lip_depth - 0.5,
+        battery_center_z + battery_diameter / 2 + 1.5
+    );
+    rib_width = 2.4;
+    rib_positions = [
+        battery_start_x + 4,
+        (battery_start_x + battery_end_x) / 2,
+        battery_end_x - 4
+    ];
+
+    // Board/battery partition, with a lead-routing notch near the JST end.
+    difference() {
+        translate([wall_thickness, partition_y, effective_floor - eps])
+            cube([
+                battery_end_x - wall_thickness + battery_end_clearance,
+                wall_thickness,
+                partition_height - effective_floor + eps
+            ]);
+        translate([
+            board_origin_x + 6.5,
+            partition_y - eps,
+            effective_floor + 1.5
+        ])
+            cube([9, wall_thickness + 2 * eps, 6]);
+    }
+
+    // Three low curved ribs cradle the protected cylindrical pack.
+    for (x = rib_positions)
+        difference() {
+            translate([
+                x - rib_width / 2,
+                battery_center_y - battery_diameter / 2
+                    - battery_radial_clearance,
+                effective_floor - eps
+            ])
+                cube([
+                    rib_width,
+                    battery_diameter + 2 * battery_radial_clearance,
+                    battery_diameter / 2 + battery_radial_clearance + eps
+                ]);
+            translate([x - rib_width, battery_center_y, battery_center_z])
+                rotate([0, 90, 0])
+                    cylinder(
+                        h = rib_width * 2,
+                        d = battery_diameter + 2 * battery_radial_clearance
+                    );
+        }
+
+    // End stops remain below the cell center so the lid can remove vertically.
+    for (x = [
+        battery_start_x - battery_end_clearance - wall_thickness,
+        battery_end_x + battery_end_clearance
+    ])
+        translate([
+            x,
+            battery_center_y - battery_diameter / 2 - battery_radial_clearance,
+            effective_floor - eps
+        ])
+            cube([
+                wall_thickness,
+                battery_diameter + 2 * battery_radial_clearance,
+                battery_diameter / 2 + 1 + eps
+            ]);
+
+    // Rear cross-strip separates the side-mounted switch body from the cell.
+    translate([
+        battery_end_x + battery_end_clearance,
+        partition_y,
+        effective_floor - eps
+    ])
+        cube([
+            case_length - wall_thickness - battery_end_x - battery_end_clearance,
+            case_width - wall_thickness - partition_y,
+            min(body_height - effective_floor, switch_center_z
+                + switch_body_diameter / 2 + switch_wire_allowance
+                - effective_floor) + eps
+        ]);
+}
+
+module body_positive() {
+    union() {
+        difference() {
+            rounded_box([case_length, case_width, body_height], corner_radius);
+            translate([wall_thickness, wall_thickness, effective_floor])
+                rounded_box([
+                    case_length - 2 * wall_thickness,
+                    case_width - 2 * wall_thickness,
+                    body_height - effective_floor + eps
+                ], max(0.6, corner_radius - wall_thickness));
+        }
+        board_standoffs();
+        lid_bosses();
+        if (battery_enabled)
+            battery_cradle();
+        if (tripod_insert_enabled)
+            translate([case_length / 2, case_width / 2, 0])
+                cylinder(h = effective_floor, d = tripod_boss_diameter);
+    }
+}
+
+module body_cutouts() {
+    // Board mounting insert pockets, loaded from above before the Feather.
+    for (mx = mount_x, my = mount_y)
+        translate([board_origin_x + mx, board_origin_y + my, 0])
+            insert_pocket(
+                m25_insert_hole_diameter,
+                m25_insert_length + insert_melt_relief,
+                board_bottom_z
+            );
+
+    // Lid insert pockets, loaded from the top of the body.
+    for (p = lid_boss_xy)
+        translate([p[0], p[1], 0])
+            insert_pocket(
+                m25_insert_hole_diameter,
+                m25_insert_length + insert_melt_relief,
+                body_height
+            );
+
+    // USB-C cable opening. Connector center is from the official ESP32 V2 PCB.
+    usb_center_z = board_top_z + 1.6 + usb_vertical_offset;
+    face_rounded_cutout(
+        "front",
+        board_origin_y + usb_center_y,
+        usb_center_z,
+        usb_opening_width + hole_compensation,
+        usb_opening_height + hole_compensation,
+        usb_opening_radius
+    );
+
+    if (battery_enabled) {
+        face_circle_cutout(
+            "right",
+            switch_center_x,
+            switch_center_z,
+            switch_hole_diameter + switch_hole_compensation
+        );
+        // Clear the switch body and its prewired terminals through the rear bay.
+        translate([
+            switch_center_x,
+            case_width - wall_thickness + eps,
+            switch_center_z
+        ])
+            rotate([90, 0, 0])
+                cylinder(
+                    h = switch_body_length + switch_wire_allowance
+                        + wall_thickness + eps,
+                    d = switch_body_diameter + 2 * fit_clearance
+                );
+    }
+
+    if (tripod_insert_enabled) {
+        translate([case_length / 2, case_width / 2, 0]) {
+            translate([0, 0, -eps])
+                cylinder(
+                    h = effective_floor + 2 * eps,
+                    d = tripod_thread_clearance_diameter + hole_compensation
+                );
+            insert_pocket(
+                tripod_insert_hole_diameter,
+                tripod_insert_length + insert_melt_relief,
+                effective_floor
+            );
+        }
+    }
+
+    for (entry = extra_cutouts)
+        custom_wall_cutout(entry);
+}
+
+module body() {
+    difference() {
+        body_positive();
+        body_cutouts();
+    }
+}
+
+module lid_plate_positive() {
+    union() {
+        rounded_box([case_length, case_width, lid_thickness], corner_radius);
+        // Inset rim: exported pointing upward so the outer lid face prints flat.
+        translate([
+            wall_thickness + fit_clearance,
+            wall_thickness + fit_clearance,
+            lid_thickness
+        ])
+            linear_extrude(height = lid_lip_depth)
+                difference() {
+                    rounded_rect_2d([
+                        case_length - 2 * (wall_thickness + fit_clearance),
+                        case_width - 2 * (wall_thickness + fit_clearance)
+                    ], max(0.6, corner_radius - wall_thickness));
+                    translate([lid_lip_thickness, lid_lip_thickness])
+                        rounded_rect_2d([
+                            case_length - 2 * (
+                                wall_thickness + fit_clearance
+                                + lid_lip_thickness
+                            ),
+                            case_width - 2 * (
+                                wall_thickness + fit_clearance
+                                + lid_lip_thickness
+                            )
+                        ], max(0.5, corner_radius - wall_thickness
+                            - lid_lip_thickness));
+                }
+    }
+}
+
+module beveled_oled_window() {
+    inner_size = oled_visible_size;
+    outer_size = [oled_visible_size[0] + 3, oled_visible_size[1] + 3];
+    center = [
+        board_origin_x + oled_visible_min[0] + oled_visible_size[0] / 2,
+        board_origin_y + oled_visible_min[1] + oled_visible_size[1] / 2
+    ];
+    hull() {
+        translate([center[0], center[1], -eps])
+            linear_extrude(height = eps)
+                centered_rounded_rect_2d(outer_size, 1.5);
+        translate([center[0], center[1], lid_thickness - eps])
+            linear_extrude(height = 2 * eps)
+                centered_rounded_rect_2d(inner_size, 0.8);
+    }
+}
+
+module oled_button_lid_cutout(xy) {
+    center = [board_origin_x + xy[0], board_origin_y + xy[1]];
+    shaft_size = [
+        button_cap_size[0] + fit_clearance * 2,
+        button_cap_size[1] + fit_clearance * 2
+    ];
+    recess_size = [
+        button_flange_size[0] + fit_clearance * 2,
+        button_flange_size[1] + fit_clearance * 2
+    ];
+    recess_depth = button_flange_thickness + button_travel;
+    translate([center[0], center[1], -eps])
+        centered_rounded_prism(
+            shaft_size,
+            lid_thickness + 2 * eps,
+            shaft_size[1] / 2
+        );
+    translate([center[0], center[1], lid_thickness - recess_depth])
+        centered_rounded_prism(
+            recess_size,
+            recess_depth + lid_lip_depth + eps,
+            recess_size[1] / 2
+        );
+}
+
+module lid_cutouts() {
+    // Through holes plus shallow counterbores for flush M2.5 socket heads.
+    for (p = lid_boss_xy) {
+        translate([p[0], p[1], -eps])
+            cylinder(
+                h = lid_thickness + lid_lip_depth + 2 * eps,
+                d = m25_screw_clearance + hole_compensation
+            );
+        translate([p[0], p[1], -eps])
+            cylinder(
+                h = lid_screw_head_height + eps,
+                d = lid_screw_head_diameter + hole_compensation
+            );
+    }
+
+    if (top_profile == "oled128x64") {
+        beveled_oled_window();
+        if (button_a) oled_button_lid_cutout(oled_button_a_xy);
+        if (button_b) oled_button_lid_cutout(oled_button_b_xy);
+        if (button_c) oled_button_lid_cutout(oled_button_c_xy);
+        if (button_reset) oled_button_lid_cutout(oled_button_reset_xy);
+    }
+}
+
+module lid() {
+    difference() {
+        lid_plate_positive();
+        lid_cutouts();
+    }
+}
+
+module one_oled_button() {
+    recess_depth = button_flange_thickness + button_travel;
+    stem_height = lid_thickness - recess_depth + button_projection;
+    // Print outer cap face down. The flange and contact nub build upward.
+    centered_rounded_prism(
+        button_cap_size,
+        stem_height,
+        button_cap_size[1] / 2
+    );
+    translate([0, 0, stem_height])
+        centered_rounded_prism(
+            button_flange_size,
+            button_flange_thickness,
+            button_flange_size[1] / 2
+        );
+    translate([0, 0, stem_height + button_flange_thickness])
+        cylinder(h = button_contact_extension, d = 3);
+}
+
+module buttons() {
+    enabled = [
+        button_a,
+        button_b,
+        button_c,
+        button_reset
+    ];
+    count_enabled = len([for (v = enabled) if (v) 1]);
+    if (count_enabled == 0)
+        echo("No OLED buttons are enabled.");
+    for (i = [0 : len(enabled) - 1])
+        if (enabled[i])
+            translate([i * (button_flange_size[0] + 3), 0, 0])
+                one_oled_button();
+}
+
+module reference_board() {
+    color([0.05, 0.25, 0.55, 0.75])
+        translate([board_origin_x, board_origin_y, board_bottom_z])
+            rounded_box([feather_length, feather_width, board_thickness], 2.54);
+    color([0.12, 0.45, 0.75, 0.45])
+        for (i = [1 : wing_count])
+            translate([
+                board_origin_x,
+                board_origin_y,
+                board_top_z + i * wing_pitch - board_thickness
+            ])
+                rounded_box(
+                    [feather_length, feather_width, board_thickness], 2.54
+                );
+}
+
+module reference_top_feature() {
+    if (top_profile == "gps")
+        color([0.92, 0.78, 0.35, 0.8])
+            translate([
+                board_origin_x + 31,
+                board_origin_y + (feather_width - 15) / 2,
+                top_pcb_z
+            ])
+                cube([15, 15, gps_antenna_height]);
+    else if (top_profile == "oled128x64") {
+        color([0.12, 0.12, 0.12, 0.9])
+            translate([
+                board_origin_x + oled_visible_min[0],
+                board_origin_y + oled_visible_min[1],
+                top_pcb_z
+            ])
+                cube([
+                    oled_visible_size[0],
+                    oled_visible_size[1],
+                    oled_component_height
+                ]);
+        color([0.6, 0.6, 0.6, 0.9])
+            for (xy = [
+                oled_button_a_xy,
+                oled_button_b_xy,
+                oled_button_c_xy,
+                oled_button_reset_xy
+            ])
+                translate([
+                    board_origin_x + xy[0],
+                    board_origin_y + xy[1],
+                    top_pcb_z
+                ])
+                    cylinder(h = 1.6, d = 2.1);
+    } else
+        color([0.3, 0.65, 0.35, 0.6])
+            translate([
+                board_origin_x + 10,
+                board_origin_y + 4,
+                top_pcb_z
+            ])
+                cube([
+                    feather_length - 20,
+                    feather_width - 8,
+                    generic_component_height
+                ]);
+}
+
+module reference_battery_and_switch() {
+    if (battery_enabled) {
+        color([0.35, 0.18, 0.55, 0.75])
+            translate([battery_start_x, battery_center_y, battery_center_z])
+                rotate([0, 90, 0])
+                    cylinder(h = battery_length, d = battery_diameter);
+        color([0.8, 0.15, 0.1, 0.65])
+            translate([
+                switch_center_x,
+                case_width - wall_thickness,
+                switch_center_z
+            ])
+                rotate([90, 0, 0]) {
+                    cylinder(h = switch_body_length, d = switch_body_diameter);
+                    translate([0, 0, -1.5])
+                        cylinder(h = 1.5, d = switch_flange_diameter);
+                    translate([0, 0, -3])
+                        cylinder(h = 3, d = switch_cap_diameter);
+                }
+    }
+}
+
+module assembly() {
+    color([0.82, 0.84, 0.88, 1]) body();
+    if ($preview && show_references) {
+        reference_board();
+        reference_top_feature();
+        reference_battery_and_switch();
+    }
+    // Printable lid is mirrored into its installed orientation and exploded up.
+    color([0.92, 0.92, 0.95, 0.88])
+        translate([0, case_width, body_height + lid_thickness + exploded_view])
+            rotate([180, 0, 0])
+                lid();
+}
+
+module coupon_hole(x, y, diameter, depth) {
+    translate([x, y, -eps]) cylinder(h = depth + 2 * eps, d = diameter);
+}
+
+module insert_coupon() {
+    spacing = 15;
+    coupon_length = spacing * len(coupon_steps) + 8;
+    coupon_width = 32;
+    coupon_height = max(
+        m25_insert_length + insert_melt_relief + 1.2,
+        tripod_insert_length + insert_melt_relief + 1.2
+    );
+    difference() {
+        rounded_box([coupon_length, coupon_width, coupon_height], 3);
+        for (i = [0 : len(coupon_steps) - 1]) {
+            x = 7 + i * spacing;
+            coupon_hole(
+                x, 8,
+                m25_insert_hole_diameter + coupon_steps[i],
+                m25_insert_length + insert_melt_relief
+            );
+            coupon_hole(
+                x, 23,
+                tripod_insert_hole_diameter + coupon_steps[i],
+                tripod_insert_length + insert_melt_relief
+            );
+        }
+    }
+}
+
+module switch_coupon() {
+    spacing = 18;
+    coupon_length = spacing * len(coupon_steps) + 6;
+    coupon_width = 24;
+    coupon_height = wall_thickness;
+    difference() {
+        rounded_box([coupon_length, coupon_width, coupon_height], 3);
+        for (i = [0 : len(coupon_steps) - 1])
+            translate([6 + i * spacing, coupon_width / 2, -eps])
+                cylinder(
+                    h = coupon_height + 2 * eps,
+                    d = switch_hole_diameter + coupon_steps[i]
+                );
+    }
+}
+
+module fit_coupon() {
+    segment_length = 34;
+    base_width = 16;
+    base_height = 6;
+    cavity_size = [segment_length - 8, base_width - 8];
+    male_size = [
+        cavity_size[0] - 2 * fit_clearance,
+        cavity_size[1] - 2 * fit_clearance
+    ];
+    difference() {
+        rounded_box([segment_length, base_width, base_height], 2);
+        translate([4, 4, 2])
+            cube([segment_length - 8, base_width - 8, base_height]);
+    }
+    translate([segment_length + 5, 0, 0])
+        union() {
+            cube([segment_length, base_width, lid_thickness]);
+            translate([
+                4 + fit_clearance,
+                4 + fit_clearance,
+                lid_thickness - eps
+            ])
+                linear_extrude(height = lid_lip_depth + eps)
+                    difference() {
+                        rounded_rect_2d(male_size, 1);
+                        translate([lid_lip_thickness, lid_lip_thickness])
+                            rounded_rect_2d([
+                                male_size[0] - 2 * lid_lip_thickness,
+                                male_size[1] - 2 * lid_lip_thickness
+                            ], 0.5);
+                    }
+        }
+}
+
+if (part == "assembly")
+    assembly();
+else if (part == "body")
+    body();
+else if (part == "lid")
+    lid();
+else if (part == "buttons")
+    buttons();
+else if (part == "insert_coupon")
+    insert_coupon();
+else if (part == "switch_coupon")
+    switch_coupon();
+else if (part == "fit_coupon")
+    fit_coupon();
+else
+    assert(false, str("Unknown part: ", part));

cases/gps/source/render_stl_previews.py

@@ -0,0 +1,127 @@
+"""Render six inspection views of an STL using Blender.
+
+Usage:
+    blender --background --python tools/render_stl_previews.py -- \
+        input.stl output-directory basename [comma-separated-views]
+"""
+
+import os
+import sys
+
+import bpy
+from mathutils import Vector
+
+
+def arguments():
+    args = sys.argv[sys.argv.index("--") + 1 :]
+    if len(args) not in (3, 4):
+        raise SystemExit(
+            "expected: input.stl output-directory basename [comma-separated-views]"
+        )
+    requested_views = args[3].split(",") if len(args) == 4 else None
+    return args[0], args[1], args[2], requested_views
+
+
+def look_at(camera, target):
+    direction = Vector(target) - camera.location
+    camera.rotation_euler = direction.to_track_quat("-Z", "Y").to_euler()
+
+
+def render_view(camera, center, span, name, direction, output_dir, basename):
+    distance = span * 2.2
+    camera.location = Vector(center) + Vector(direction).normalized() * distance
+    look_at(camera, center)
+    camera.data.type = "ORTHO"
+    camera.data.ortho_scale = span * 1.35
+    bpy.context.scene.render.filepath = os.path.join(
+        output_dir, f"{basename}_{name}.png"
+    )
+    bpy.ops.render.render(write_still=True)
+
+
+def main():
+    input_path, output_dir, basename, requested_views = arguments()
+    os.makedirs(output_dir, exist_ok=True)
+
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+    bpy.ops.wm.stl_import(filepath=os.path.abspath(input_path))
+    model = bpy.context.selected_objects[0]
+    model.name = "Feather case"
+
+    material = bpy.data.materials.new("Case material")
+    material.diffuse_color = (0.16, 0.42, 0.72, 1.0)
+    material.metallic = 0.0
+    material.roughness = 0.45
+    model.data.materials.append(material)
+
+    corners = [model.matrix_world @ Vector(corner) for corner in model.bound_box]
+    mins = Vector([min(v[i] for v in corners) for i in range(3)])
+    maxs = Vector([max(v[i] for v in corners) for i in range(3)])
+    center = (mins + maxs) / 2
+    span = max(maxs - mins)
+
+    world = bpy.data.worlds.new("Inspection world")
+    world.use_nodes = True
+    world.node_tree.nodes["Background"].inputs["Color"].default_value = (
+        0.035,
+        0.04,
+        0.05,
+        1,
+    )
+    world.node_tree.nodes["Background"].inputs["Strength"].default_value = 0.5
+    bpy.context.scene.world = world
+
+    camera_data = bpy.data.cameras.new("Camera")
+    camera = bpy.data.objects.new("Camera", camera_data)
+    bpy.context.collection.objects.link(camera)
+    bpy.context.scene.camera = camera
+
+    key_data = bpy.data.lights.new("Key", type="AREA")
+    key_data.energy = 900
+    key_data.shape = "DISK"
+    key_data.size = span
+    key = bpy.data.objects.new("Key", key_data)
+    key.location = center + Vector((span, -span, span * 1.5))
+    bpy.context.collection.objects.link(key)
+
+    fill_data = bpy.data.lights.new("Fill", type="AREA")
+    fill_data.energy = 500
+    fill_data.size = span
+    fill = bpy.data.objects.new("Fill", fill_data)
+    fill.location = center + Vector((-span, span, span))
+    bpy.context.collection.objects.link(fill)
+
+    scene = bpy.context.scene
+    scene.render.engine = "BLENDER_WORKBENCH"
+    scene.render.resolution_x = 800
+    scene.render.resolution_y = 600
+    scene.render.resolution_percentage = 100
+    scene.render.image_settings.file_format = "PNG"
+    scene.render.film_transparent = False
+    scene.display.shading.light = "STUDIO"
+    scene.display.shading.color_type = "MATERIAL"
+    scene.display.shading.show_shadows = True
+    scene.display.shading.show_cavity = True
+    scene.display.shading.cavity_type = "BOTH"
+    scene.display.shading.curvature_ridge_factor = 1.5
+    scene.display.shading.curvature_valley_factor = 1.2
+
+    views = {
+        "iso": (1, -1, 0.8),
+        "front": (-1, 0, 0),
+        "back": (1, 0, 0),
+        "left": (0, -1, 0),
+        "right": (0, 1, 0),
+        "top": (0, 0, 1),
+    }
+    selected = requested_views or list(views)
+    unknown = sorted(set(selected) - set(views))
+    if unknown:
+        raise SystemExit(f"unknown views: {', '.join(unknown)}")
+    for name in selected:
+        direction = views[name]
+        render_view(camera, center, span, name, direction, output_dir, basename)
+
+
+if __name__ == "__main__":
+    main()

feather_case.scad

@@ -0,0 +1,871 @@
+/*
+ * Parametric enclosure for the Adafruit ESP32 Feather V2 and FeatherWings.
+ *
+ * Coordinate system:
+ *   X: USB-C wall (0) toward the rear of the case
+ *   Y: non-battery side (0) toward the battery/JST side
+ *   Z: outside bottom (0) upward
+ *
+ * Board coordinates are derived from Adafruit's Eagle PCB files:
+ *   https://github.com/adafruit/Adafruit-ESP32-Feather-V2-PCB
+ *   https://github.com/adafruit/Adafruit-OLED-FeatherWing-PCB
+ */
+
+/* [Output] */
+part = "assembly"; // [assembly,body,lid,buttons,insert_coupon,switch_coupon,fit_coupon]
+exploded_view = 8; // [0:1:20]
+show_references = true;
+
+/* [Stack] */
+top_profile = "generic"; // [generic,gps,oled128x64]
+wing_count = 1; // [1:1:8]
+wing_pitch = 11; // [7:0.1:16]
+stack_height_override = 0; // [0:0.1:100]
+generic_component_height = 3; // [0:0.1:30]
+generic_top_gap = 2; // [0.5:0.1:10]
+gps_antenna_height = 4;
+gps_top_gap = 5;
+oled_component_height = 2.4;
+oled_face_gap = 0.8;
+
+/* [OLED controls] */
+button_a = true;
+button_b = true;
+button_c = true;
+button_reset = false;
+button_projection = 1.5; // [0.5:0.1:3]
+button_cap_size = [5, 3.2];
+button_flange_size = [6.6, 3.6];
+button_flange_thickness = 0.9;
+button_travel = 0.5;
+button_contact_extension = 0.7;
+
+/* [Battery and switch] */
+battery_enabled = false;
+battery_length = 69;
+battery_diameter = 18;
+battery_radial_clearance = 0.6;
+battery_end_clearance = 1;
+switch_hole_diameter = 12;
+switch_hole_compensation = 0.3;
+switch_cap_diameter = 8;
+switch_flange_diameter = 16.2;
+switch_body_length = 24;
+switch_body_diameter = 12;
+switch_wire_allowance = 3;
+
+/* [Tripod mount] */
+tripod_insert_enabled = false;
+tripod_insert_length = 6.4;
+tripod_insert_hole_diameter = 8.8;
+tripod_thread_clearance_diameter = 6.8;
+tripod_boss_diameter = 14;
+
+/* [M2.5 inserts] */
+m25_insert_length = 4;
+m25_insert_hole_diameter = 3.7;
+m25_screw_clearance = 2.8;
+m25_boss_diameter = 7;
+insert_entry_chamfer = 0.6;
+insert_melt_relief = 0.8;
+
+/* [Shell and fit] */
+wall_thickness = 2.4;
+floor_thickness = 2.4;
+lid_thickness = 3.2;
+corner_radius = 4;
+board_bottom_clearance = 5.4;
+board_side_clearance = 7;
+board_rear_clearance = 4;
+usb_board_wall_gap = 1.2;
+lid_lip_depth = 2.4;
+lid_lip_thickness = 1.2;
+fit_clearance = 0.35;
+hole_compensation = 0.2;
+lid_screw_head_diameter = 5.2;
+lid_screw_head_height = 2.5;
+
+/* [USB-C opening] */
+usb_opening_width = 12.5;
+usb_opening_height = 7;
+usb_opening_radius = 1.5;
+usb_vertical_offset = 0;
+
+/* [Custom wall cutouts] */
+// Entry format: [face, shape, u, z, width, height, radius]
+// face: front, rear, left, right. u is Y on front/rear and X on left/right.
+// shape: circle, rect, roundrect, slot. Circle uses width as its diameter.
+extra_cutouts = [];
+
+/* [Calibration] */
+coupon_steps = [-0.3, -0.15, 0, 0.15, 0.3];
+
+$fn = $preview ? 36 : 72;
+eps = 0.02;
+
+// Adafruit Feather mechanical reference, millimetres.
+feather_length = 50.8;
+feather_width = 22.86;
+board_thickness = 1.6;
+mount_x = [2.54, 48.26];
+mount_y = [2.54, 20.32];
+usb_center_y = 11.43;
+
+// Official 128x64 OLED FeatherWing geometry in Feather-board coordinates.
+oled_visible_min = [11.42, 3.78];
+oled_visible_size = [30, 15.3];
+oled_button_a_xy = [4.318, 15.875];
+oled_button_b_xy = [4.318, 11.43];
+oled_button_c_xy = [4.318, 6.985];
+oled_button_reset_xy = [7.366, 20.828];
+
+effective_floor = tripod_insert_enabled
+    ? max(floor_thickness, tripod_insert_length + insert_melt_relief + 1.2)
+    : floor_thickness;
+effective_board_clearance = max(
+    board_bottom_clearance,
+    m25_insert_length + insert_melt_relief + 0.6
+);
+
+board_origin_x = wall_thickness + usb_board_wall_gap;
+board_origin_y = wall_thickness + board_side_clearance;
+board_bottom_z = effective_floor + effective_board_clearance;
+board_top_z = board_bottom_z + board_thickness;
+
+computed_top_pcb_z = board_top_z + wing_count * wing_pitch;
+top_pcb_z = stack_height_override > 0
+    ? board_top_z + stack_height_override
+    : computed_top_pcb_z;
+profile_component_height =
+    top_profile == "gps" ? gps_antenna_height :
+    top_profile == "oled128x64" ? oled_component_height :
+    generic_component_height;
+profile_top_gap =
+    top_profile == "gps" ? gps_top_gap :
+    top_profile == "oled128x64" ? oled_face_gap :
+    generic_top_gap;
+
+partition_y = board_origin_y + feather_width + 1;
+battery_center_y = partition_y + wall_thickness + battery_radial_clearance
+    + battery_diameter / 2;
+battery_start_x = board_origin_x + battery_end_clearance;
+battery_end_x = battery_start_x + battery_length;
+switch_center_x = battery_end_x + max(
+    switch_body_diameter / 2 + 0.8,
+    switch_flange_diameter / 2 + 0.5
+);
+
+case_length_plain = board_origin_x + feather_length
+    + board_rear_clearance + wall_thickness;
+case_length_battery = switch_center_x + switch_flange_diameter / 2
+    + 1.2 + wall_thickness;
+case_length = battery_enabled ? max(case_length_plain, case_length_battery)
+    : case_length_plain;
+
+case_width_plain = board_origin_y + feather_width
+    + board_side_clearance + wall_thickness;
+case_width_battery = battery_center_y + battery_diameter / 2
+    + battery_radial_clearance + wall_thickness;
+case_width = battery_enabled ? max(case_width_plain, case_width_battery)
+    : case_width_plain;
+
+battery_center_z = effective_floor + battery_radial_clearance
+    + battery_diameter / 2;
+switch_center_z = max(
+    effective_floor + switch_flange_diameter / 2 + 1,
+    battery_center_z
+);
+electronics_ceiling_z = top_pcb_z + profile_component_height + profile_top_gap;
+battery_ceiling_z = battery_enabled
+    ? max(
+        battery_center_z + battery_diameter / 2 + battery_radial_clearance,
+        switch_center_z + switch_flange_diameter / 2 + 1
+    )
+    : 0;
+body_height = max(electronics_ceiling_z, battery_ceiling_z);
+
+lid_boss_r = m25_boss_diameter / 2;
+lid_boss_wall_overlap = 0.6;
+lid_boss_xy = [
+    [
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap,
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap
+    ],
+    [
+        case_length - wall_thickness - lid_boss_r + lid_boss_wall_overlap,
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap
+    ],
+    [
+        wall_thickness + lid_boss_r - lid_boss_wall_overlap,
+        case_width - wall_thickness - lid_boss_r + lid_boss_wall_overlap
+    ],
+    [
+        case_length - wall_thickness - lid_boss_r + lid_boss_wall_overlap,
+        case_width - wall_thickness - lid_boss_r + lid_boss_wall_overlap
+    ]
+];
+
+assert(wing_count >= 1, "wing_count must be at least one");
+assert(top_profile == "generic" || top_profile == "gps"
+    || top_profile == "oled128x64", "Unsupported top_profile");
+assert(wall_thickness >= 1.2, "wall_thickness is too small for 0.6 mm FDM");
+assert(lid_lip_thickness >= 1.2, "lid lip needs at least two 0.6 mm lines");
+assert(m25_boss_diameter > m25_insert_hole_diameter + 2,
+    "M2.5 boss does not have enough radial material");
+assert(!tripod_insert_enabled
+    || tripod_boss_diameter > tripod_insert_hole_diameter + 3,
+    "Tripod insert boss does not have enough radial material");
+
+function clamp(v, lo, hi) = min(max(v, lo), hi);
+
+module rounded_rect_2d(size, radius) {
+    r = clamp(radius, 0.01, min(size[0], size[1]) / 2 - 0.01);
+    hull() {
+        for (x = [r, size[0] - r], y = [r, size[1] - r])
+            translate([x, y]) circle(r = r);
+    }
+}
+
+module centered_rounded_rect_2d(size, radius) {
+    translate([-size[0] / 2, -size[1] / 2])
+        rounded_rect_2d(size, radius);
+}
+
+module centered_rounded_prism(size, height, radius) {
+    linear_extrude(height = height)
+        centered_rounded_rect_2d(size, radius);
+}
+
+module rounded_box(size, radius) {
+    linear_extrude(height = size[2])
+        rounded_rect_2d([size[0], size[1]], radius);
+}
+
+module insert_pocket(diameter, depth, entry_z, downward = true) {
+    bore_d = diameter + hole_compensation;
+    if (downward) {
+        translate([0, 0, entry_z - depth])
+            cylinder(h = depth + eps, d = bore_d);
+        translate([0, 0, entry_z - insert_entry_chamfer])
+            cylinder(
+                h = insert_entry_chamfer + eps,
+                d1 = bore_d,
+                d2 = bore_d + 2 * insert_entry_chamfer
+            );
+    } else {
+        translate([0, 0, entry_z - eps])
+            cylinder(h = depth + eps, d = bore_d);
+        translate([0, 0, entry_z - eps])
+            cylinder(
+                h = insert_entry_chamfer + eps,
+                d1 = bore_d + 2 * insert_entry_chamfer,
+                d2 = bore_d
+            );
+    }
+}
+
+module face_rounded_cutout(face, u, z, width, height, radius) {
+    r = clamp(radius, 0.01, min(width, height) / 2);
+    depth = wall_thickness + 2 * eps;
+    if (face == "front" || face == "rear") {
+        x0 = face == "front" ? -eps : case_length - wall_thickness - eps;
+        hull()
+            for (yy = [u - width / 2 + r, u + width / 2 - r],
+                 zz = [z - height / 2 + r, z + height / 2 - r])
+                translate([x0, yy, zz])
+                    rotate([0, 90, 0]) cylinder(h = depth, r = r);
+    } else if (face == "left" || face == "right") {
+        y0 = face == "left" ? -eps : case_width - wall_thickness - eps;
+        hull()
+            for (xx = [u - width / 2 + r, u + width / 2 - r],
+                 zz = [z - height / 2 + r, z + height / 2 - r])
+                translate([xx, y0, zz])
+                    rotate([-90, 0, 0]) cylinder(h = depth, r = r);
+    }
+}
+
+module face_circle_cutout(face, u, z, diameter) {
+    depth = wall_thickness + 2 * eps;
+    if (face == "front")
+        translate([-eps, u, z])
+            rotate([0, 90, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "rear")
+        translate([case_length - wall_thickness - eps, u, z])
+            rotate([0, 90, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "left")
+        translate([u, -eps, z])
+            rotate([-90, 0, 0]) cylinder(h = depth, d = diameter);
+    else if (face == "right")
+        translate([u, case_width - wall_thickness - eps, z])
+            rotate([-90, 0, 0]) cylinder(h = depth, d = diameter);
+}
+
+module custom_wall_cutout(entry) {
+    face = entry[0];
+    shape = entry[1];
+    u = entry[2];
+    z = entry[3];
+    width = entry[4];
+    height = len(entry) > 5 ? entry[5] : width;
+    radius = len(entry) > 6 ? entry[6] : min(width, height) / 2;
+    assert(face == "front" || face == "rear"
+        || face == "left" || face == "right", "Invalid cutout face");
+    assert(shape == "circle" || shape == "rect"
+        || shape == "roundrect" || shape == "slot", "Invalid cutout shape");
+    assert(z - height / 2 >= effective_floor,
+        "Cutout intersects the floor");
+    assert(z + height / 2 <= body_height - lid_lip_depth,
+        "Cutout intersects the lid locating lip");
+    assert(
+        (face == "front" || face == "rear")
+            ? u - width / 2 >= 0 && u + width / 2 <= case_width
+            : u - width / 2 >= 0 && u + width / 2 <= case_length,
+        "Cutout extends beyond its wall"
+    );
+
+    if (shape == "circle")
+        face_circle_cutout(face, u, z, width);
+    else
+        face_rounded_cutout(
+            face, u, z, width, height,
+            shape == "rect" ? 0.02 :
+            shape == "slot" ? min(width, height) / 2 : radius
+        );
+}
+
+module board_standoffs() {
+    for (mx = mount_x, my = mount_y)
+        translate([
+            board_origin_x + mx,
+            board_origin_y + my,
+            effective_floor - eps
+        ])
+            cylinder(
+                h = effective_board_clearance + eps,
+                d = m25_boss_diameter
+            );
+}
+
+module lid_bosses() {
+    for (p = lid_boss_xy)
+        translate([p[0], p[1], effective_floor - eps])
+            cylinder(
+                h = body_height - effective_floor + eps,
+                d = m25_boss_diameter
+            );
+}
+
+module battery_cradle() {
+    partition_height = min(
+        body_height - lid_lip_depth - 0.5,
+        battery_center_z + battery_diameter / 2 + 1.5
+    );
+    rib_width = 2.4;
+    rib_positions = [
+        battery_start_x + 4,
+        (battery_start_x + battery_end_x) / 2,
+        battery_end_x - 4
+    ];
+
+    // Board/battery partition, with a lead-routing notch near the JST end.
+    difference() {
+        translate([wall_thickness, partition_y, effective_floor - eps])
+            cube([
+                battery_end_x - wall_thickness + battery_end_clearance,
+                wall_thickness,
+                partition_height - effective_floor + eps
+            ]);
+        translate([
+            board_origin_x + 6.5,
+            partition_y - eps,
+            effective_floor + 1.5
+        ])
+            cube([9, wall_thickness + 2 * eps, 6]);
+    }
+
+    // Three low curved ribs cradle the protected cylindrical pack.
+    for (x = rib_positions)
+        difference() {
+            translate([
+                x - rib_width / 2,
+                battery_center_y - battery_diameter / 2
+                    - battery_radial_clearance,
+                effective_floor - eps
+            ])
+                cube([
+                    rib_width,
+                    battery_diameter + 2 * battery_radial_clearance,
+                    battery_diameter / 2 + battery_radial_clearance + eps
+                ]);
+            translate([x - rib_width, battery_center_y, battery_center_z])
+                rotate([0, 90, 0])
+                    cylinder(
+                        h = rib_width * 2,
+                        d = battery_diameter + 2 * battery_radial_clearance
+                    );
+        }
+
+    // End stops remain below the cell center so the lid can remove vertically.
+    for (x = [
+        battery_start_x - battery_end_clearance - wall_thickness,
+        battery_end_x + battery_end_clearance
+    ])
+        translate([
+            x,
+            battery_center_y - battery_diameter / 2 - battery_radial_clearance,
+            effective_floor - eps
+        ])
+            cube([
+                wall_thickness,
+                battery_diameter + 2 * battery_radial_clearance,
+                battery_diameter / 2 + 1 + eps
+            ]);
+
+    // Rear cross-strip separates the side-mounted switch body from the cell.
+    translate([
+        battery_end_x + battery_end_clearance,
+        partition_y,
+        effective_floor - eps
+    ])
+        cube([
+            case_length - wall_thickness - battery_end_x - battery_end_clearance,
+            case_width - wall_thickness - partition_y,
+            min(body_height - effective_floor, switch_center_z
+                + switch_body_diameter / 2 + switch_wire_allowance
+                - effective_floor) + eps
+        ]);
+}
+
+module body_positive() {
+    union() {
+        difference() {
+            rounded_box([case_length, case_width, body_height], corner_radius);
+            translate([wall_thickness, wall_thickness, effective_floor])
+                rounded_box([
+                    case_length - 2 * wall_thickness,
+                    case_width - 2 * wall_thickness,
+                    body_height - effective_floor + eps
+                ], max(0.6, corner_radius - wall_thickness));
+        }
+        board_standoffs();
+        lid_bosses();
+        if (battery_enabled)
+            battery_cradle();
+        if (tripod_insert_enabled)
+            translate([case_length / 2, case_width / 2, 0])
+                cylinder(h = effective_floor, d = tripod_boss_diameter);
+    }
+}
+
+module body_cutouts() {
+    // Board mounting insert pockets, loaded from above before the Feather.
+    for (mx = mount_x, my = mount_y)
+        translate([board_origin_x + mx, board_origin_y + my, 0])
+            insert_pocket(
+                m25_insert_hole_diameter,
+                m25_insert_length + insert_melt_relief,
+                board_bottom_z
+            );
+
+    // Lid insert pockets, loaded from the top of the body.
+    for (p = lid_boss_xy)
+        translate([p[0], p[1], 0])
+            insert_pocket(
+                m25_insert_hole_diameter,
+                m25_insert_length + insert_melt_relief,
+                body_height
+            );
+
+    // USB-C cable opening. Connector center is from the official ESP32 V2 PCB.
+    usb_center_z = board_top_z + 1.6 + usb_vertical_offset;
+    face_rounded_cutout(
+        "front",
+        board_origin_y + usb_center_y,
+        usb_center_z,
+        usb_opening_width + hole_compensation,
+        usb_opening_height + hole_compensation,
+        usb_opening_radius
+    );
+
+    if (battery_enabled) {
+        face_circle_cutout(
+            "right",
+            switch_center_x,
+            switch_center_z,
+            switch_hole_diameter + switch_hole_compensation
+        );
+        // Clear the switch body and its prewired terminals through the rear bay.
+        translate([
+            switch_center_x,
+            case_width - wall_thickness + eps,
+            switch_center_z
+        ])
+            rotate([90, 0, 0])
+                cylinder(
+                    h = switch_body_length + switch_wire_allowance
+                        + wall_thickness + eps,
+                    d = switch_body_diameter + 2 * fit_clearance
+                );
+    }
+
+    if (tripod_insert_enabled) {
+        translate([case_length / 2, case_width / 2, 0]) {
+            translate([0, 0, -eps])
+                cylinder(
+                    h = effective_floor + 2 * eps,
+                    d = tripod_thread_clearance_diameter + hole_compensation
+                );
+            insert_pocket(
+                tripod_insert_hole_diameter,
+                tripod_insert_length + insert_melt_relief,
+                effective_floor
+            );
+        }
+    }
+
+    for (entry = extra_cutouts)
+        custom_wall_cutout(entry);
+}
+
+module body() {
+    difference() {
+        body_positive();
+        body_cutouts();
+    }
+}
+
+module lid_plate_positive() {
+    union() {
+        rounded_box([case_length, case_width, lid_thickness], corner_radius);
+        // Inset rim: exported pointing upward so the outer lid face prints flat.
+        translate([
+            wall_thickness + fit_clearance,
+            wall_thickness + fit_clearance,
+            lid_thickness
+        ])
+            linear_extrude(height = lid_lip_depth)
+                difference() {
+                    rounded_rect_2d([
+                        case_length - 2 * (wall_thickness + fit_clearance),
+                        case_width - 2 * (wall_thickness + fit_clearance)
+                    ], max(0.6, corner_radius - wall_thickness));
+                    translate([lid_lip_thickness, lid_lip_thickness])
+                        rounded_rect_2d([
+                            case_length - 2 * (
+                                wall_thickness + fit_clearance
+                                + lid_lip_thickness
+                            ),
+                            case_width - 2 * (
+                                wall_thickness + fit_clearance
+                                + lid_lip_thickness
+                            )
+                        ], max(0.5, corner_radius - wall_thickness
+                            - lid_lip_thickness));
+                }
+    }
+}
+
+module beveled_oled_window() {
+    inner_size = oled_visible_size;
+    outer_size = [oled_visible_size[0] + 3, oled_visible_size[1] + 3];
+    center = [
+        board_origin_x + oled_visible_min[0] + oled_visible_size[0] / 2,
+        board_origin_y + oled_visible_min[1] + oled_visible_size[1] / 2
+    ];
+    hull() {
+        translate([center[0], center[1], -eps])
+            linear_extrude(height = eps)
+                centered_rounded_rect_2d(outer_size, 1.5);
+        translate([center[0], center[1], lid_thickness - eps])
+            linear_extrude(height = 2 * eps)
+                centered_rounded_rect_2d(inner_size, 0.8);
+    }
+}
+
+module oled_button_lid_cutout(xy) {
+    center = [board_origin_x + xy[0], board_origin_y + xy[1]];
+    shaft_size = [
+        button_cap_size[0] + fit_clearance * 2,
+        button_cap_size[1] + fit_clearance * 2
+    ];
+    recess_size = [
+        button_flange_size[0] + fit_clearance * 2,
+        button_flange_size[1] + fit_clearance * 2
+    ];
+    recess_depth = button_flange_thickness + button_travel;
+    translate([center[0], center[1], -eps])
+        centered_rounded_prism(
+            shaft_size,
+            lid_thickness + 2 * eps,
+            shaft_size[1] / 2
+        );
+    translate([center[0], center[1], lid_thickness - recess_depth])
+        centered_rounded_prism(
+            recess_size,
+            recess_depth + lid_lip_depth + eps,
+            recess_size[1] / 2
+        );
+}
+
+module lid_cutouts() {
+    // Through holes plus shallow counterbores for flush M2.5 socket heads.
+    for (p = lid_boss_xy) {
+        translate([p[0], p[1], -eps])
+            cylinder(
+                h = lid_thickness + lid_lip_depth + 2 * eps,
+                d = m25_screw_clearance + hole_compensation
+            );
+        translate([p[0], p[1], -eps])
+            cylinder(
+                h = lid_screw_head_height + eps,
+                d = lid_screw_head_diameter + hole_compensation
+            );
+    }
+
+    if (top_profile == "oled128x64") {
+        beveled_oled_window();
+        if (button_a) oled_button_lid_cutout(oled_button_a_xy);
+        if (button_b) oled_button_lid_cutout(oled_button_b_xy);
+        if (button_c) oled_button_lid_cutout(oled_button_c_xy);
+        if (button_reset) oled_button_lid_cutout(oled_button_reset_xy);
+    }
+}
+
+module lid() {
+    difference() {
+        lid_plate_positive();
+        lid_cutouts();
+    }
+}
+
+module one_oled_button() {
+    recess_depth = button_flange_thickness + button_travel;
+    stem_height = lid_thickness - recess_depth + button_projection;
+    // Print outer cap face down. The flange and contact nub build upward.
+    centered_rounded_prism(
+        button_cap_size,
+        stem_height,
+        button_cap_size[1] / 2
+    );
+    translate([0, 0, stem_height])
+        centered_rounded_prism(
+            button_flange_size,
+            button_flange_thickness,
+            button_flange_size[1] / 2
+        );
+    translate([0, 0, stem_height + button_flange_thickness])
+        cylinder(h = button_contact_extension, d = 3);
+}
+
+module buttons() {
+    enabled = [
+        button_a,
+        button_b,
+        button_c,
+        button_reset
+    ];
+    count_enabled = len([for (v = enabled) if (v) 1]);
+    if (count_enabled == 0)
+        echo("No OLED buttons are enabled.");
+    for (i = [0 : len(enabled) - 1])
+        if (enabled[i])
+            translate([i * (button_flange_size[0] + 3), 0, 0])
+                one_oled_button();
+}
+
+module reference_board() {
+    color([0.05, 0.25, 0.55, 0.75])
+        translate([board_origin_x, board_origin_y, board_bottom_z])
+            rounded_box([feather_length, feather_width, board_thickness], 2.54);
+    color([0.12, 0.45, 0.75, 0.45])
+        for (i = [1 : wing_count])
+            translate([
+                board_origin_x,
+                board_origin_y,
+                board_top_z + i * wing_pitch - board_thickness
+            ])
+                rounded_box(
+                    [feather_length, feather_width, board_thickness], 2.54
+                );
+}
+
+module reference_top_feature() {
+    if (top_profile == "gps")
+        color([0.92, 0.78, 0.35, 0.8])
+            translate([
+                board_origin_x + 31,
+                board_origin_y + (feather_width - 15) / 2,
+                top_pcb_z
+            ])
+                cube([15, 15, gps_antenna_height]);
+    else if (top_profile == "oled128x64") {
+        color([0.12, 0.12, 0.12, 0.9])
+            translate([
+                board_origin_x + oled_visible_min[0],
+                board_origin_y + oled_visible_min[1],
+                top_pcb_z
+            ])
+                cube([
+                    oled_visible_size[0],
+                    oled_visible_size[1],
+                    oled_component_height
+                ]);
+        color([0.6, 0.6, 0.6, 0.9])
+            for (xy = [
+                oled_button_a_xy,
+                oled_button_b_xy,
+                oled_button_c_xy,
+                oled_button_reset_xy
+            ])
+                translate([
+                    board_origin_x + xy[0],
+                    board_origin_y + xy[1],
+                    top_pcb_z
+                ])
+                    cylinder(h = 1.6, d = 2.1);
+    } else
+        color([0.3, 0.65, 0.35, 0.6])
+            translate([
+                board_origin_x + 10,
+                board_origin_y + 4,
+                top_pcb_z
+            ])
+                cube([
+                    feather_length - 20,
+                    feather_width - 8,
+                    generic_component_height
+                ]);
+}
+
+module reference_battery_and_switch() {
+    if (battery_enabled) {
+        color([0.35, 0.18, 0.55, 0.75])
+            translate([battery_start_x, battery_center_y, battery_center_z])
+                rotate([0, 90, 0])
+                    cylinder(h = battery_length, d = battery_diameter);
+        color([0.8, 0.15, 0.1, 0.65])
+            translate([
+                switch_center_x,
+                case_width - wall_thickness,
+                switch_center_z
+            ])
+                rotate([90, 0, 0]) {
+                    cylinder(h = switch_body_length, d = switch_body_diameter);
+                    translate([0, 0, -1.5])
+                        cylinder(h = 1.5, d = switch_flange_diameter);
+                    translate([0, 0, -3])
+                        cylinder(h = 3, d = switch_cap_diameter);
+                }
+    }
+}
+
+module assembly() {
+    color([0.82, 0.84, 0.88, 1]) body();
+    if ($preview && show_references) {
+        reference_board();
+        reference_top_feature();
+        reference_battery_and_switch();
+    }
+    // Printable lid is mirrored into its installed orientation and exploded up.
+    color([0.92, 0.92, 0.95, 0.88])
+        translate([0, case_width, body_height + lid_thickness + exploded_view])
+            rotate([180, 0, 0])
+                lid();
+}
+
+module coupon_hole(x, y, diameter, depth) {
+    translate([x, y, -eps]) cylinder(h = depth + 2 * eps, d = diameter);
+}
+
+module insert_coupon() {
+    spacing = 15;
+    coupon_length = spacing * len(coupon_steps) + 8;
+    coupon_width = 32;
+    coupon_height = max(
+        m25_insert_length + insert_melt_relief + 1.2,
+        tripod_insert_length + insert_melt_relief + 1.2
+    );
+    difference() {
+        rounded_box([coupon_length, coupon_width, coupon_height], 3);
+        for (i = [0 : len(coupon_steps) - 1]) {
+            x = 7 + i * spacing;
+            coupon_hole(
+                x, 8,
+                m25_insert_hole_diameter + coupon_steps[i],
+                m25_insert_length + insert_melt_relief
+            );
+            coupon_hole(
+                x, 23,
+                tripod_insert_hole_diameter + coupon_steps[i],
+                tripod_insert_length + insert_melt_relief
+            );
+        }
+    }
+}
+
+module switch_coupon() {
+    spacing = 18;
+    coupon_length = spacing * len(coupon_steps) + 6;
+    coupon_width = 24;
+    coupon_height = wall_thickness;
+    difference() {
+        rounded_box([coupon_length, coupon_width, coupon_height], 3);
+        for (i = [0 : len(coupon_steps) - 1])
+            translate([6 + i * spacing, coupon_width / 2, -eps])
+                cylinder(
+                    h = coupon_height + 2 * eps,
+                    d = switch_hole_diameter + coupon_steps[i]
+                );
+    }
+}
+
+module fit_coupon() {
+    segment_length = 34;
+    base_width = 16;
+    base_height = 6;
+    cavity_size = [segment_length - 8, base_width - 8];
+    male_size = [
+        cavity_size[0] - 2 * fit_clearance,
+        cavity_size[1] - 2 * fit_clearance
+    ];
+    difference() {
+        rounded_box([segment_length, base_width, base_height], 2);
+        translate([4, 4, 2])
+            cube([segment_length - 8, base_width - 8, base_height]);
+    }
+    translate([segment_length + 5, 0, 0])
+        union() {
+            cube([segment_length, base_width, lid_thickness]);
+            translate([
+                4 + fit_clearance,
+                4 + fit_clearance,
+                lid_thickness - eps
+            ])
+                linear_extrude(height = lid_lip_depth + eps)
+                    difference() {
+                        rounded_rect_2d(male_size, 1);
+                        translate([lid_lip_thickness, lid_lip_thickness])
+                            rounded_rect_2d([
+                                male_size[0] - 2 * lid_lip_thickness,
+                                male_size[1] - 2 * lid_lip_thickness
+                            ], 0.5);
+                    }
+        }
+}
+
+if (part == "assembly")
+    assembly();
+else if (part == "body")
+    body();
+else if (part == "lid")
+    lid();
+else if (part == "buttons")
+    buttons();
+else if (part == "insert_coupon")
+    insert_coupon();
+else if (part == "switch_coupon")
+    switch_coupon();
+else if (part == "fit_coupon")
+    fit_coupon();
+else
+    assert(false, str("Unknown part: ", part));

lib/feather_case_wizard.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "digest"
+require "fileutils"
+require "json"
+require "open3"
+require "pathname"
+require "time"
+require "tmpdir"
+require "yaml"
+
+require "highline"
+
+require_relative "feather_case_wizard/config"
+require_relative "feather_case_wizard/toolchain"
+require_relative "feather_case_wizard/package_builder"
+require_relative "feather_case_wizard/wizard"
+require_relative "feather_case_wizard/cli"
+
+module FeatherCaseWizard
+  ROOT = Pathname(__dir__).join("..").expand_path.freeze
+  CASES_ROOT = ROOT.join("cases").freeze
+  MODEL_SOURCE = ROOT.join("feather_case.scad").freeze
+  RENDERER_SOURCE = ROOT.join("tools/render_stl_previews.py").freeze
+end
+

lib/feather_case_wizard/cli.rb

@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+module FeatherCaseWizard
+  class CLI
+    def initialize(ui: HighLine.new, cases_root: CASES_ROOT,
+                   model_source: MODEL_SOURCE, renderer_source: RENDERER_SOURCE,
+                   toolchain: Toolchain.new)
+      @ui = ui
+      @cases_root = Pathname(cases_root)
+      @model_source = Pathname(model_source)
+      @renderer_source = Pathname(renderer_source)
+      @toolchain = toolchain
+      @wizard = Wizard.new(ui: ui)
+    end
+
+    def run
+      @ui.say(@ui.color("Feather Case Wizard", :bold))
+      loop do
+        action = @ui.choose("\nWhat would you like to do?") do |menu|
+          menu.choice("Create a new case") { :create }
+          menu.choice("Edit an existing case") { :edit }
+          menu.choice("Rebuild an existing case") { :rebuild }
+          menu.choice("Exit") { :exit }
+        end
+        return 0 if action == :exit
+
+        case action
+        when :create then create_case
+        when :edit then edit_case
+        when :rebuild then rebuild_case
+        end
+      rescue ConfigError, ToolError, Errno::EACCES => e
+        @ui.say(@ui.color("\n#{e.message}", :red))
+      rescue Interrupt
+        @ui.say("\nCancelled.")
+        return 130
+      end
+    end
+
+    private
+
+    def create_case
+      config = @wizard.create
+      destination = config.package_dir(@cases_root)
+      if destination.exist? &&
+         !@ui.agree("#{destination} already exists. Replace it? (y/n) ") { |q| q.default = "no" }
+        return
+      end
+      build(config, @model_source, @renderer_source) if @wizard.confirm_build(config)
+    end
+
+    def edit_case
+      path = choose_case
+      return unless path
+
+      config = Config.load(path)
+      package = path.dirname
+      source = package.join("source/feather_case.scad")
+      renderer = package.join("source/render_stl_previews.py")
+      source, renderer = choose_generator(config, source, renderer)
+      config = @wizard.edit(config)
+      build(config, source, renderer) if @wizard.confirm_build(config)
+    end
+
+    def rebuild_case
+      path = choose_case
+      return unless path
+
+      config = Config.load(path)
+      return unless @wizard.confirm_build(config)
+
+      package = path.dirname
+      build(config, package.join("source/feather_case.scad"),
+            package.join("source/render_stl_previews.py"))
+    end
+
+    def choose_case
+      paths = Dir.glob(@cases_root.join("*/case.yml")).sort.map { |item| Pathname(item) }
+      if paths.empty?
+        @ui.say("No saved cases found under #{@cases_root}.")
+        return nil
+      end
+      @ui.choose("Choose a saved case") do |menu|
+        paths.each do |path|
+          label = Config.load(path).name
+          menu.choice("#{label} (#{path.dirname.basename})") { path }
+        rescue ConfigError
+          menu.choice("Invalid configuration (#{path.dirname.basename})") { path }
+        end
+      end
+    end
+
+    def choose_generator(config, snapshot, renderer)
+      return [@model_source, @renderer_source] unless snapshot.file?
+
+      snapshot_sha = Digest::SHA256.file(snapshot).hexdigest
+      current_sha = Digest::SHA256.file(@model_source).hexdigest
+      return [snapshot, renderer] if snapshot_sha == current_sha
+
+      @ui.say("This case uses a different generator snapshot.")
+      upgrade = @ui.agree("Upgrade it to the current generator? (y/n) ") do |question|
+        question.default = "no"
+      end
+      upgrade ? [@model_source, @renderer_source] : [snapshot, renderer]
+    end
+
+    def build(config, source, renderer)
+      destination = PackageBuilder.new(
+        config, root: @cases_root, toolchain: @toolchain,
+        model_source: source, renderer_source: renderer,
+        reporter: ->(message) { @ui.say("  #{message}…") }
+      ).build!
+      @ui.say(@ui.color("\nGenerated #{destination}", :green))
+    end
+  end
+end

lib/feather_case_wizard/config.rb

@@ -0,0 +1,347 @@
+# frozen_string_literal: true
+
+module FeatherCaseWizard
+  class ConfigError < StandardError; end
+
+  class Config
+    SCHEMA_VERSION = 1
+    PROFILES = %w[generic gps oled128x64].freeze
+    FORMATS = %w[stl 3mf].freeze
+    FACES = %w[front rear left right].freeze
+    SHAPES = %w[circle rect roundrect slot].freeze
+    COUPONS = %w[insert_coupon switch_coupon fit_coupon].freeze
+
+    DEFAULT_PARAMETERS = {
+      "top_profile" => "generic",
+      "wing_count" => 1,
+      "wing_pitch" => 11.0,
+      "stack_height_override" => 0.0,
+      "generic_component_height" => 3.0,
+      "generic_top_gap" => 2.0,
+      "gps_antenna_height" => 4.0,
+      "gps_top_gap" => 5.0,
+      "oled_component_height" => 2.4,
+      "oled_face_gap" => 0.8,
+      "button_a" => true,
+      "button_b" => true,
+      "button_c" => true,
+      "button_reset" => false,
+      "button_projection" => 1.5,
+      "button_cap_size" => [5.0, 3.2],
+      "button_flange_size" => [6.6, 3.6],
+      "button_flange_thickness" => 0.9,
+      "button_travel" => 0.5,
+      "button_contact_extension" => 0.7,
+      "battery_enabled" => false,
+      "battery_length" => 69.0,
+      "battery_diameter" => 18.0,
+      "battery_radial_clearance" => 0.6,
+      "battery_end_clearance" => 1.0,
+      "switch_hole_diameter" => 12.0,
+      "switch_hole_compensation" => 0.3,
+      "switch_cap_diameter" => 8.0,
+      "switch_flange_diameter" => 16.2,
+      "switch_body_length" => 24.0,
+      "switch_body_diameter" => 12.0,
+      "switch_wire_allowance" => 3.0,
+      "tripod_insert_enabled" => false,
+      "tripod_insert_length" => 6.4,
+      "tripod_insert_hole_diameter" => 8.8,
+      "tripod_thread_clearance_diameter" => 6.8,
+      "tripod_boss_diameter" => 14.0,
+      "m25_insert_length" => 4.0,
+      "m25_insert_hole_diameter" => 3.7,
+      "m25_screw_clearance" => 2.8,
+      "m25_boss_diameter" => 7.0,
+      "insert_entry_chamfer" => 0.6,
+      "insert_melt_relief" => 0.8,
+      "wall_thickness" => 2.4,
+      "floor_thickness" => 2.4,
+      "lid_thickness" => 3.2,
+      "corner_radius" => 4.0,
+      "board_bottom_clearance" => 5.4,
+      "board_side_clearance" => 7.0,
+      "board_rear_clearance" => 4.0,
+      "usb_board_wall_gap" => 1.2,
+      "lid_lip_depth" => 2.4,
+      "lid_lip_thickness" => 1.2,
+      "fit_clearance" => 0.35,
+      "hole_compensation" => 0.2,
+      "lid_screw_head_diameter" => 5.2,
+      "lid_screw_head_height" => 2.5,
+      "usb_opening_width" => 12.5,
+      "usb_opening_height" => 7.0,
+      "usb_opening_radius" => 1.5,
+      "usb_vertical_offset" => 0.0
+    }.freeze
+
+    ADVANCED_FIELDS = {
+      "Stack" => %w[wing_pitch generic_component_height generic_top_gap
+                    gps_antenna_height gps_top_gap oled_component_height oled_face_gap],
+      "Shell and fit" => %w[wall_thickness floor_thickness lid_thickness corner_radius
+                            board_bottom_clearance board_side_clearance board_rear_clearance
+                            usb_board_wall_gap lid_lip_depth lid_lip_thickness fit_clearance
+                            hole_compensation lid_screw_head_diameter lid_screw_head_height],
+      "M2.5 inserts" => %w[m25_insert_length m25_insert_hole_diameter
+                           m25_screw_clearance m25_boss_diameter
+                           insert_entry_chamfer insert_melt_relief],
+      "Tripod insert" => %w[tripod_insert_length tripod_insert_hole_diameter
+                            tripod_thread_clearance_diameter tripod_boss_diameter],
+      "Battery and switch" => %w[battery_length battery_diameter battery_radial_clearance
+                                 battery_end_clearance switch_hole_diameter
+                                 switch_hole_compensation switch_cap_diameter
+                                 switch_flange_diameter switch_body_length
+                                 switch_body_diameter switch_wire_allowance],
+      "USB-C opening" => %w[usb_opening_width usb_opening_height
+                            usb_opening_radius usb_vertical_offset],
+      "OLED buttons" => %w[button_projection button_flange_thickness
+                           button_travel button_contact_extension]
+    }.freeze
+
+    attr_reader :data
+
+    def self.create(name:, slug:)
+      new(
+        "schema_version" => SCHEMA_VERSION,
+        "name" => name,
+        "slug" => slug,
+        "generator" => {},
+        "parameters" => deep_copy(DEFAULT_PARAMETERS),
+        "cutouts" => [],
+        "outputs" => {
+          "formats" => ["3mf"],
+          "coupons" => [],
+          "assembly_exploded_view" => 8
+        }
+      )
+    end
+
+    def self.load(path)
+      raw = YAML.safe_load_file(path, permitted_classes: [], permitted_symbols: [],
+                               aliases: false)
+      raise ConfigError, "Configuration must be a YAML mapping" unless raw.is_a?(Hash)
+
+      new(raw)
+    rescue Psych::Exception => e
+      raise ConfigError, "Cannot read configuration: #{e.message}"
+    end
+
+    def self.deep_copy(value)
+      Marshal.load(Marshal.dump(value))
+    end
+
+    def initialize(data)
+      @data = stringify_keys(data)
+      normalize!
+      validate!
+    end
+
+    def name = data.fetch("name")
+    def slug = data.fetch("slug")
+    def parameters = data.fetch("parameters")
+    def cutouts = data.fetch("cutouts")
+    def outputs = data.fetch("outputs")
+    def generator = data.fetch("generator")
+
+    def package_dir(root = CASES_ROOT)
+      root.join(slug)
+    end
+
+    def printable_parts
+      parts = %w[body lid]
+      if parameters["top_profile"] == "oled128x64" &&
+         %w[button_a button_b button_c button_reset].any? { |key| parameters[key] }
+        parts << "buttons"
+      end
+      parts + outputs["coupons"]
+    end
+
+    def model_parameters
+      parameters.merge("extra_cutouts" => scad_cutouts)
+    end
+
+    def dimensions
+      p = parameters
+      effective_floor = p["tripod_insert_enabled"] ?
+        [p["floor_thickness"], p["tripod_insert_length"] + p["insert_melt_relief"] + 1.2].max :
+        p["floor_thickness"]
+      effective_board_clearance = [
+        p["board_bottom_clearance"],
+        p["m25_insert_length"] + p["insert_melt_relief"] + 0.6
+      ].max
+      board_origin_x = p["wall_thickness"] + p["usb_board_wall_gap"]
+      board_origin_y = p["wall_thickness"] + p["board_side_clearance"]
+      board_top_z = effective_floor + effective_board_clearance + 1.6
+      top_pcb_z = board_top_z + (
+        p["stack_height_override"].positive? ?
+          p["stack_height_override"] : p["wing_count"] * p["wing_pitch"]
+      )
+      component_height, top_gap = case p["top_profile"]
+                                  when "gps"
+                                    [p["gps_antenna_height"], p["gps_top_gap"]]
+                                  when "oled128x64"
+                                    [p["oled_component_height"], p["oled_face_gap"]]
+                                  else
+                                    [p["generic_component_height"], p["generic_top_gap"]]
+                                  end
+      plain_length = board_origin_x + 50.8 + p["board_rear_clearance"] +
+                     p["wall_thickness"]
+      plain_width = board_origin_y + 22.86 + p["board_side_clearance"] +
+                    p["wall_thickness"]
+      if p["battery_enabled"]
+        partition_y = board_origin_y + 22.86 + 1
+        battery_y = partition_y + p["wall_thickness"] +
+                    p["battery_radial_clearance"] + p["battery_diameter"] / 2
+        battery_start_x = board_origin_x + p["battery_end_clearance"]
+        battery_end_x = battery_start_x + p["battery_length"]
+        switch_x = battery_end_x + [
+          p["switch_body_diameter"] / 2 + 0.8,
+          p["switch_flange_diameter"] / 2 + 0.5
+        ].max
+        length = [plain_length, switch_x + p["switch_flange_diameter"] / 2 +
+                  1.2 + p["wall_thickness"]].max
+        width = [plain_width, battery_y + p["battery_diameter"] / 2 +
+                 p["battery_radial_clearance"] + p["wall_thickness"]].max
+        battery_z = effective_floor + p["battery_radial_clearance"] +
+                    p["battery_diameter"] / 2
+        switch_z = [
+          effective_floor + p["switch_flange_diameter"] / 2 + 1,
+          battery_z
+        ].max
+        battery_ceiling = [
+          battery_z + p["battery_diameter"] / 2 + p["battery_radial_clearance"],
+          switch_z + p["switch_flange_diameter"] / 2 + 1
+        ].max
+      else
+        length = plain_length
+        width = plain_width
+        battery_ceiling = 0
+      end
+      {
+        "length" => length,
+        "width" => width,
+        "height" => [top_pcb_z + component_height + top_gap, battery_ceiling].max,
+        "floor" => effective_floor,
+        "lip_bottom" => [top_pcb_z + component_height + top_gap, battery_ceiling].max -
+                        p["lid_lip_depth"]
+      }
+    end
+
+    def scad_cutouts
+      dims = dimensions
+      cutouts.map do |cutout|
+        face = cutout.fetch("face")
+        horizontal = cutout.fetch("horizontal")
+        u = case face
+            when "front" then dims["width"] - horizontal
+            when "rear", "left" then horizontal
+            when "right" then dims["length"] - horizontal
+            end
+        width = cutout.fetch("width")
+        height = cutout.fetch("height", width)
+        radius = cutout.fetch("radius", [width, height].min / 2)
+        [face, cutout.fetch("shape"), u, cutout.fetch("z"), width, height, radius]
+      end
+    end
+
+    def to_yaml
+      data["resolved"] = {"extra_cutouts" => scad_cutouts}
+      data.to_yaml(line_width: -1)
+    end
+
+    def validate!
+      raise ConfigError, "Unsupported schema_version" unless data["schema_version"] == SCHEMA_VERSION
+      raise ConfigError, "Project name cannot be empty" if name.to_s.strip.empty?
+      unless slug.match?(/\A[a-z0-9]+(?:-[a-z0-9]+)*\z/)
+        raise ConfigError, "Slug must contain lowercase letters, numbers, and single hyphens"
+      end
+      raise ConfigError, "Unsupported top profile" unless PROFILES.include?(parameters["top_profile"])
+      raise ConfigError, "wing_count must be between 1 and 8" unless (1..8).cover?(parameters["wing_count"])
+      raise ConfigError, "At least one export format is required" if outputs["formats"].empty?
+      unless (outputs["formats"] - FORMATS).empty?
+        raise ConfigError, "Unsupported export format"
+      end
+      unless (outputs["coupons"] - COUPONS).empty?
+        raise ConfigError, "Unsupported calibration coupon"
+      end
+
+      positive = DEFAULT_PARAMETERS.keys - %w[usb_vertical_offset stack_height_override]
+      positive.each do |key|
+        value = parameters[key]
+        next if value == true || value == false
+        next if value.is_a?(Array) && value.all? { |item| item.to_f.positive? }
+        next unless value.is_a?(Numeric)
+        raise ConfigError, "#{key} must be positive" unless value.to_f.positive?
+      end
+      raise ConfigError, "stack_height_override cannot be negative" if
+        parameters["stack_height_override"].negative?
+      raise ConfigError, "wall_thickness must be at least 1.2 mm" if
+        parameters["wall_thickness"] < 1.2
+      raise ConfigError, "lid_lip_thickness must be at least 1.2 mm" if
+        parameters["lid_lip_thickness"] < 1.2
+
+      validate_cutouts!
+      self
+    end
+
+    private
+
+    def normalize!
+      data["schema_version"] = Integer(data.fetch("schema_version", SCHEMA_VERSION))
+      data["generator"] ||= {}
+      data["parameters"] = self.class.deep_copy(DEFAULT_PARAMETERS).merge(data["parameters"] || {})
+      data["cutouts"] ||= []
+      data["outputs"] ||= {}
+      data["outputs"]["formats"] ||= ["3mf"]
+      data["outputs"]["coupons"] ||= []
+      data["outputs"]["assembly_exploded_view"] ||= 8
+    rescue ArgumentError, TypeError => e
+      raise ConfigError, "Invalid configuration value: #{e.message}"
+    end
+
+    def validate_cutouts!
+      dims = dimensions
+      names = {}
+      cutouts.each do |cutout|
+        name = cutout["name"].to_s.strip
+        raise ConfigError, "Every cutout needs a name" if name.empty?
+        raise ConfigError, "Duplicate cutout name: #{name}" if names[name]
+        names[name] = true
+        face = cutout["face"]
+        shape = cutout["shape"]
+        raise ConfigError, "Invalid face for #{name}" unless FACES.include?(face)
+        raise ConfigError, "Invalid shape for #{name}" unless SHAPES.include?(shape)
+        width = Float(cutout["width"])
+        height = Float(cutout.fetch("height", width))
+        horizontal = Float(cutout["horizontal"])
+        z = Float(cutout["z"])
+        wall_width = %w[front rear].include?(face) ? dims["width"] : dims["length"]
+        unless horizontal - width / 2 >= 0 && horizontal + width / 2 <= wall_width
+          raise ConfigError, "#{name} extends beyond the #{face} wall"
+        end
+        if z - height / 2 < dims["floor"]
+          raise ConfigError, "#{name} intersects the case floor"
+        end
+        if z + height / 2 > dims["lip_bottom"]
+          raise ConfigError, "#{name} intersects the lid locating lip"
+        end
+        radius = Float(cutout.fetch("radius", [width, height].min / 2))
+        raise ConfigError, "#{name} dimensions must be positive" unless
+          width.positive? && height.positive? && radius.positive?
+      rescue ArgumentError, TypeError, KeyError => e
+        raise ConfigError, "Invalid cutout #{name.inspect}: #{e.message}"
+      end
+    end
+
+    def stringify_keys(value)
+      case value
+      when Hash
+        value.to_h { |key, item| [key.to_s, stringify_keys(item)] }
+      when Array
+        value.map { |item| stringify_keys(item) }
+      else
+        value
+      end
+    end
+  end
+end

lib/feather_case_wizard/package_builder.rb

@@ -0,0 +1,200 @@
+# frozen_string_literal: true
+
+module FeatherCaseWizard
+  class PackageBuilder
+    attr_reader :config, :root, :toolchain, :model_source, :renderer_source
+
+    def initialize(config, root: CASES_ROOT, toolchain: Toolchain.new,
+                   model_source: MODEL_SOURCE, renderer_source: RENDERER_SOURCE,
+                   reporter: nil)
+      @config = config
+      @root = Pathname(root)
+      @toolchain = toolchain
+      @model_source = Pathname(model_source)
+      @renderer_source = Pathname(renderer_source)
+      @reporter = reporter || ->(_message) {}
+    end
+
+    def build!
+      toolchain.check!
+      verify_sources!
+      config.validate!
+      config.generator["sha256"] = Digest::SHA256.file(model_source).hexdigest
+      config.generator["created_with"] ||= "feather-case-wizard"
+
+      FileUtils.mkdir_p(root)
+      destination = config.package_dir(root)
+      stage = Pathname(Dir.mktmpdir(".#{config.slug}-stage-", root.to_s))
+      prepare_package(stage, destination)
+      install_atomically(stage, destination)
+      destination
+    ensure
+      FileUtils.rm_rf(stage) if stage&.exist?
+    end
+
+    private
+
+    def verify_sources!
+      raise ToolError, "Missing model source: #{model_source}" unless model_source.file?
+      raise ToolError, "Missing preview renderer: #{renderer_source}" unless renderer_source.file?
+    end
+
+    def prepare_package(stage, previous)
+      source_dir = stage.join("source")
+      FileUtils.mkdir_p(source_dir)
+      FileUtils.cp(model_source, source_dir.join("feather_case.scad"))
+      FileUtils.cp(renderer_source, source_dir.join("render_stl_previews.py"))
+      FileUtils.cp(ROOT.join("templates/standalone_build.rb"), stage.join("build.rb"))
+
+      copy_history(previous, stage)
+      write_configuration(stage)
+      generate_exports(stage)
+      generate_previews(stage)
+      write_summary(stage)
+    end
+
+    def copy_history(previous, stage)
+      history = stage.join("history")
+      if previous.directory?
+        old_history = previous.join("history")
+        FileUtils.cp_r(old_history, history) if old_history.directory?
+        FileUtils.mkdir_p(history)
+        stamp = Time.now.utc.strftime("%Y%m%dT%H%M%S.%6NZ")
+        FileUtils.cp(previous.join("case.yml"), history.join("case-#{stamp}.yml")) if
+          previous.join("case.yml").file?
+        old_source = previous.join("source/feather_case.scad")
+        if old_source.file? &&
+           Digest::SHA256.file(old_source).hexdigest != config.generator["sha256"]
+          FileUtils.cp(old_source, history.join("feather_case-#{stamp}.scad"))
+        end
+      end
+    end
+
+    def write_configuration(stage)
+      File.write(stage.join("case.yml"), config.to_yaml)
+      values = config.parameters.to_h do |key, value|
+        [key, openscad_literal(value)]
+      end
+      customizer = {
+        "parameterSets" => {config.slug => values},
+        "fileFormatVersion" => "1"
+      }
+      File.write(stage.join("parameters.json"), JSON.pretty_generate(customizer) + "\n")
+      FileUtils.chmod(0o755, stage.join("build.rb"))
+    end
+
+    def generate_exports(stage)
+      config.outputs["formats"].each do |format|
+        directory = stage.join("exports", format)
+        FileUtils.mkdir_p(directory)
+        config.printable_parts.each do |part|
+          report("Exporting #{part}.#{format}")
+          export_model(stage, directory.join("#{part}.#{format}"), part)
+        end
+      end
+    end
+
+    def generate_previews(stage)
+      previews = stage.join("previews")
+      scratch = stage.join(".preview-meshes")
+      FileUtils.mkdir_p([previews, scratch])
+      assembly_stl = scratch.join("assembly.stl")
+      report("Preparing assembly preview")
+      export_model(stage, assembly_stl, "assembly",
+                   "exploded_view" => config.outputs["assembly_exploded_view"],
+                   "show_references" => false)
+      render(stage, assembly_stl, previews, "assembly")
+
+      config.printable_parts.each do |part|
+        report("Rendering #{part} preview")
+        mesh = scratch.join("#{part}.stl")
+        export_model(stage, mesh, part) unless mesh.file?
+        render(stage, mesh, previews, part, ["iso"])
+      end
+      FileUtils.rm_rf(scratch)
+    end
+
+    def export_model(stage, output, part, overrides = {})
+      model = stage.join("source/feather_case.scad")
+      parameters = config.model_parameters.merge(overrides).merge("part" => part)
+      command = [toolchain.openscad, "-o", output.to_s]
+      parameters.each do |name, value|
+        command.concat(["-D", "#{name}=#{openscad_literal(value)}"])
+      end
+      command << model.to_s
+      toolchain.run!(*command)
+      raise ToolError, "OpenSCAD did not create #{output}" unless output.file? && output.size.positive?
+    end
+
+    def render(stage, mesh, output_dir, basename, views = nil)
+      renderer = stage.join("source/render_stl_previews.py")
+      command = [
+        toolchain.blender, "--background", "-noaudio", "--python", renderer.to_s, "--",
+        mesh.to_s, output_dir.to_s, basename
+      ]
+      command << views.join(",") if views
+      toolchain.run!(*command, env: {"DISPLAY" => nil, "WAYLAND_DISPLAY" => nil})
+    end
+
+    def write_summary(stage)
+      dims = config.dimensions
+      parts = config.printable_parts.map { |part| "`#{part}`" }.join(", ")
+      text = <<~MARKDOWN
+        # #{config.name}
+
+        Generated by the Feather Case Wizard.
+
+        - Top profile: `#{config.parameters["top_profile"]}`
+        - FeatherWings: #{config.parameters["wing_count"]}
+        - Battery compartment: #{config.parameters["battery_enabled"] ? "yes" : "no"}
+        - 1/4-20 insert: #{config.parameters["tripod_insert_enabled"] ? "yes" : "no"}
+        - Approximate exterior: #{format("%.1f", dims["length"])} × #{format("%.1f", dims["width"])} × #{format("%.1f", dims["height"] + config.parameters["lid_thickness"])} mm
+        - Formats: #{config.outputs["formats"].join(", ")}
+        - Parts: #{parts}
+        - Custom cutouts: #{config.cutouts.length}
+
+        Run `ruby build.rb` in this directory to regenerate exports and previews.
+        OpenSCAD and Blender must be installed. Set `OPENSCAD` or `BLENDER` to
+        override their executable paths.
+
+        To open the saved Customizer values manually:
+
+        ```bash
+        openscad -p parameters.json -P #{config.slug} source/feather_case.scad
+        ```
+
+        The 3MF files contain portable geometry only. Choose printer, filament,
+        plate, and slicing settings in Bambu Studio.
+      MARKDOWN
+      File.write(stage.join("README.md"), text)
+    end
+
+    def install_atomically(stage, destination)
+      old = root.join(".#{config.slug}-old-#{Process.pid}")
+      if destination.exist?
+        FileUtils.mv(destination, old)
+      end
+      FileUtils.mv(stage, destination)
+      FileUtils.rm_rf(old) if old.exist?
+    rescue StandardError
+      FileUtils.mv(old, destination) if old&.exist? && !destination.exist?
+      raise
+    end
+
+    def openscad_literal(value)
+      case value
+      when String then JSON.generate(value)
+      when TrueClass then "true"
+      when FalseClass then "false"
+      when Numeric then value.to_s
+      when Array then "[#{value.map { |item| openscad_literal(item) }.join(",")}]"
+      else
+        raise ConfigError, "Cannot convert #{value.inspect} to OpenSCAD"
+      end
+    end
+
+    def report(message)
+      @reporter.call(message)
+    end
+  end
+end

lib/feather_case_wizard/toolchain.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module FeatherCaseWizard
+  class ToolError < StandardError; end
+
+  class Toolchain
+    attr_reader :openscad, :blender
+
+    def initialize(env: ENV)
+      @env = env
+      @openscad = discover("OPENSCAD", "openscad")
+      @blender = discover("BLENDER", "blender")
+    end
+
+    def check!
+      missing = []
+      missing << "OpenSCAD (`sudo apt-get install openscad` or set OPENSCAD)" unless openscad
+      missing << "Blender (`sudo apt-get install blender` or set BLENDER)" unless blender
+      return self if missing.empty?
+
+      raise ToolError, "Missing required tools:\n  - #{missing.join("\n  - ")}"
+    end
+
+    def run!(*command, chdir: nil, env: {})
+      options = chdir ? {chdir: chdir} : {}
+      stdout, stderr, status = Open3.capture3(env, *command, **options)
+      return [stdout, stderr] if status.success?
+
+      detail = [stdout, stderr].reject(&:empty?).join("\n").strip
+      result = status.exitstatus || "signal #{status.termsig}"
+      raise ToolError, "Command failed (#{result}): #{command.first}\n#{detail}"
+    rescue Errno::ENOENT => e
+      raise ToolError, "Cannot run #{command.first}: #{e.message}"
+    end
+
+    private
+
+    def discover(env_name, command)
+      override = @env[env_name]
+      return File.expand_path(override) if override && File.executable?(override)
+
+      @env.fetch("PATH", "").split(File::PATH_SEPARATOR).each do |directory|
+        candidate = File.join(directory, command)
+        return candidate if File.file?(candidate) && File.executable?(candidate)
+      end
+      nil
+    end
+  end
+end

lib/feather_case_wizard/wizard.rb

@@ -0,0 +1,289 @@
+# frozen_string_literal: true
+
+module FeatherCaseWizard
+  class Wizard
+    attr_reader :ui
+
+    def initialize(ui: HighLine.new)
+      @ui = ui
+    end
+
+    def create
+      name = required_text("Case name")
+      slug = ask_slug(slugify(name))
+      configure(Config.create(name: name, slug: slug), new_case: true)
+    end
+
+    def edit(config)
+      ui.say("\nEditing #{config.name} (`#{config.slug}`)")
+      config.data["name"] = text("Case name", config.name)
+      configure(config, new_case: false)
+    end
+
+    def confirm_build(config)
+      dims = config.dimensions
+      ui.say("\n#{ui.color("Build summary", :bold)}")
+      ui.say("  Case: #{config.name} (#{config.slug})")
+      ui.say("  Profile: #{config.parameters["top_profile"]}")
+      ui.say("  Wings: #{config.parameters["wing_count"]}")
+      ui.say("  Battery: #{yes_no(config.parameters["battery_enabled"])}")
+      ui.say("  Tripod insert: #{yes_no(config.parameters["tripod_insert_enabled"])}")
+      ui.say("  Cutouts: #{config.cutouts.length}")
+      ui.say("  Size: #{format("%.1f × %.1f × %.1f mm", dims["length"], dims["width"],
+                             dims["height"] + config.parameters["lid_thickness"])}")
+      ui.say("  Parts: #{config.printable_parts.join(", ")}")
+      ui.say("  Formats: #{config.outputs["formats"].join(", ")}")
+      ui.agree("Generate this case? (y/n) ") { |question| question.default = "yes" }
+    end
+
+    private
+
+    def configure(config, new_case:)
+      choose_formats(config)
+      choose_profile(config)
+      choose_stack(config)
+      choose_features(config)
+      manage_cutouts(config)
+      choose_coupons(config)
+      advanced(config) if ui.agree("Adjust advanced dimensions? (y/n) ") do |question|
+        question.default = "no"
+      end
+      config.validate!
+      config
+    rescue ConfigError => e
+      ui.say(ui.color("Configuration error: #{e.message}", :red))
+      retry unless new_case && !ui.agree("Return to the questions? (y/n) ") { |q| q.default = "yes" }
+      raise
+    end
+
+    def choose_formats(config)
+      current = config.outputs["formats"].sort
+      label = current == %w[3mf stl] ? "both" : current.first
+      selected = ui.choose("Export format (current: #{label})") do |menu|
+        menu.choice("3MF") { ["3mf"] }
+        menu.choice("STL") { ["stl"] }
+        menu.choice("Both 3MF and STL") { %w[3mf stl] }
+        menu.default = label == "both" ? 3 : (label == "stl" ? 2 : 1)
+      end
+      config.outputs["formats"] = selected
+    end
+
+    def choose_profile(config)
+      current = config.parameters["top_profile"]
+      config.parameters["top_profile"] = ui.choose("Top FeatherWing profile") do |menu|
+        menu.choice("Generic / other") { "generic" }
+        menu.choice("GPS") { "gps" }
+        menu.choice("128×64 OLED") { "oled128x64" }
+        menu.default = {"generic" => 1, "gps" => 2, "oled128x64" => 3}.fetch(current)
+      end
+    end
+
+    def choose_stack(config)
+      p = config.parameters
+      p["wing_count"] = integer("Number of FeatherWings", p["wing_count"], 1..8)
+      measured = p["stack_height_override"].positive?
+      if ui.agree("Use a measured board-to-top-PCB stack height? (y/n) ") do |question|
+        question.default = measured ? "yes" : "no"
+      end
+        p["stack_height_override"] = number(
+          "Measured height in mm", measured ? p["stack_height_override"] :
+          p["wing_count"] * p["wing_pitch"], min: 0.1
+        )
+      else
+        p["stack_height_override"] = 0.0
+      end
+    end
+
+    def choose_features(config)
+      p = config.parameters
+      p["battery_enabled"] = agreement("Include 18650 battery compartment and switch?",
+                                        p["battery_enabled"])
+      p["tripod_insert_enabled"] = agreement("Include centered 1/4-20 insert?",
+                                              p["tripod_insert_enabled"])
+      return unless p["top_profile"] == "oled128x64"
+
+      ui.say("\nOLED captive buttons")
+      p["button_a"] = agreement("Enable button A?", p["button_a"])
+      p["button_b"] = agreement("Enable button B?", p["button_b"])
+      p["button_c"] = agreement("Enable button C?", p["button_c"])
+      p["button_reset"] = agreement("Enable reset button?", p["button_reset"])
+    end
+
+    def manage_cutouts(config)
+      loop do
+        ui.say("\nCustom cable cutouts: #{config.cutouts.empty? ? "none" :
+          config.cutouts.map { |cutout| cutout["name"] }.join(", ")}")
+        action = ui.choose("Cable cutouts") do |menu|
+          menu.choice("Done") { :done }
+          menu.choice("Add cutout") { :add }
+          menu.choice("Edit cutout") { :edit } unless config.cutouts.empty?
+          menu.choice("Remove cutout") { :remove } unless config.cutouts.empty?
+        end
+        break if action == :done
+
+        case action
+        when :add
+          config.cutouts << ask_cutout(config)
+        when :edit
+          index = choose_cutout(config, "Edit which cutout?")
+          old = config.cutouts.delete_at(index)
+          config.cutouts.insert(index, ask_cutout(config, old))
+        when :remove
+          config.cutouts.delete_at(choose_cutout(config, "Remove which cutout?"))
+        end
+      rescue ConfigError => e
+        ui.say(ui.color("Cutout not accepted: #{e.message}", :red))
+      end
+    end
+
+    def ask_cutout(config, existing = nil)
+      existing ||= {}
+      dims = config.dimensions
+      name = text("Cutout name", existing["name"] || "cable")
+      face = ui.choose("Wall") do |menu|
+        Config::FACES.each { |item| menu.choice(item) { item } }
+        menu.default = Config::FACES.index(existing["face"]).to_i + 1 if existing["face"]
+      end
+      shape = ui.choose("Shape") do |menu|
+        Config::SHAPES.each { |item| menu.choice(item) { item } }
+        menu.default = Config::SHAPES.index(existing["shape"]).to_i + 1 if existing["shape"]
+      end
+      wall_width = %w[front rear].include?(face) ? dims["width"] : dims["length"]
+      ui.say("Viewing the #{face} wall from outside: width #{format("%.1f", wall_width)} mm; " \
+             "usable vertical centers lie between the floor and lid lip.")
+      width = number(shape == "circle" ? "Diameter (mm)" : "Width (mm)",
+                     existing["width"] || 8.0, min: 0.1)
+      height = shape == "circle" ? width :
+        number("Height (mm)", existing["height"] || 6.0, min: 0.1)
+      horizontal = number("Center from the wall's left edge (mm)",
+                          existing["horizontal"] || wall_width / 2, min: width / 2,
+                          max: wall_width - width / 2)
+      min_z = dims["floor"] + height / 2
+      max_z = dims["lip_bottom"] - height / 2
+      z = number("Center height from exterior bottom (mm)",
+                 existing["z"] || (min_z + max_z) / 2, min: min_z, max: max_z)
+      radius = if shape == "roundrect"
+                 number("Corner radius (mm)", existing["radius"] ||
+                   [width, height].min / 4, min: 0.01, max: [width, height].min / 2)
+               else
+                 [width, height].min / 2
+               end
+      candidate = {
+        "name" => name, "face" => face, "shape" => shape,
+        "horizontal" => horizontal, "z" => z, "width" => width,
+        "height" => height, "radius" => radius
+      }
+      temporary = Config.new(Config.deep_copy(config.data).tap do |data|
+        data["cutouts"] = config.cutouts + [candidate]
+      end)
+      temporary.validate!
+      candidate
+    end
+
+    def choose_cutout(config, prompt)
+      ui.choose(prompt) do |menu|
+        config.cutouts.each_with_index do |cutout, index|
+          menu.choice(cutout["name"]) { index }
+        end
+      end
+    end
+
+    def choose_coupons(config)
+      selected = []
+      selected << "insert_coupon" if agreement(
+        "Export heat-set insert calibration coupon?",
+        config.outputs["coupons"].include?("insert_coupon")
+      )
+      selected << "switch_coupon" if agreement(
+        "Export switch-hole calibration coupon?",
+        config.outputs["coupons"].include?("switch_coupon")
+      )
+      selected << "fit_coupon" if agreement(
+        "Export lid-fit calibration coupon?",
+        config.outputs["coupons"].include?("fit_coupon")
+      )
+      config.outputs["coupons"] = selected
+    end
+
+    def advanced(config)
+      Config::ADVANCED_FIELDS.each do |section, fields|
+        next unless ui.agree("Adjust #{section.downcase}? (y/n) ") { |q| q.default = "no" }
+
+        ui.say("\n#{section}")
+        fields.each do |field|
+          config.parameters[field] = number(field.tr("_", " "), config.parameters[field],
+                                             min: field == "usb_vertical_offset" ? nil : 0.01)
+        end
+        next unless section == "OLED buttons"
+
+        config.parameters["button_cap_size"] = pair(
+          "button cap width,length", config.parameters["button_cap_size"]
+        )
+        config.parameters["button_flange_size"] = pair(
+          "button flange width,length", config.parameters["button_flange_size"]
+        )
+      end
+    end
+
+    def agreement(prompt, default)
+      ui.agree("#{prompt} (y/n) ") { |question| question.default = default ? "yes" : "no" }
+    end
+
+    def required_text(prompt)
+      loop do
+        value = ui.ask("#{prompt}: ").to_s.strip
+        return value unless value.empty?
+        ui.say(ui.color("A value is required.", :red))
+      end
+    end
+
+    def text(prompt, default)
+      ui.ask("#{prompt}: ") { |question| question.default = default }.to_s.strip
+    end
+
+    def ask_slug(default)
+      loop do
+        value = text("Directory slug", default)
+        return value if value.match?(/\A[a-z0-9]+(?:-[a-z0-9]+)*\z/)
+        ui.say(ui.color("Use lowercase letters, numbers, and single hyphens.", :red))
+      end
+    end
+
+    def integer(prompt, default, range)
+      loop do
+        value = ui.ask("#{prompt}: ", Integer) { |question| question.default = default }
+        return value if range.cover?(value)
+        ui.say(ui.color("Enter a value from #{range.begin} through #{range.end}.", :red))
+      end
+    end
+
+    def number(prompt, default, min: nil, max: nil)
+      loop do
+        value = ui.ask("#{prompt}: ", Float) { |question| question.default = default }.to_f
+        return value if (min.nil? || value >= min) && (max.nil? || value <= max)
+        bounds = [min && "at least #{min}", max && "at most #{max}"].compact.join(" and ")
+        ui.say(ui.color("Enter a value #{bounds}.", :red))
+      end
+    end
+
+    def pair(prompt, default)
+      loop do
+        raw = text(prompt, default.join(","))
+        values = raw.split(",").map { |item| Float(item.strip) }
+        return values if values.length == 2 && values.all?(&:positive?)
+        ui.say(ui.color("Enter two positive comma-separated dimensions.", :red))
+      rescue ArgumentError
+        ui.say(ui.color("Enter two numeric comma-separated dimensions.", :red))
+      end
+    end
+
+    def slugify(name)
+      name.downcase.gsub(/[^a-z0-9]+/, "-").gsub(/\A-|-?\z/, "").yield_self do |slug|
+        slug.empty? ? "feather-case" : slug
+      end
+    end
+
+    def yes_no(value) = value ? "yes" : "no"
+  end
+end
+

templates/standalone_build.rb

@@ -0,0 +1,123 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "fileutils"
+require "json"
+require "open3"
+require "pathname"
+require "tmpdir"
+require "yaml"
+
+ROOT = Pathname(__dir__).expand_path
+
+def executable(env_name, command)
+  override = ENV[env_name]
+  return File.expand_path(override) if override && File.executable?(override)
+
+  ENV.fetch("PATH", "").split(File::PATH_SEPARATOR).each do |directory|
+    candidate = File.join(directory, command)
+    return candidate if File.file?(candidate) && File.executable?(candidate)
+  end
+  nil
+end
+
+def literal(value)
+  case value
+  when String then JSON.generate(value)
+  when TrueClass then "true"
+  when FalseClass then "false"
+  when Numeric then value.to_s
+  when Array then "[#{value.map { |item| literal(item) }.join(",")}]"
+  else raise "Cannot convert #{value.inspect} to OpenSCAD"
+  end
+end
+
+def run!(*command, env: {})
+  stdout, stderr, status = Open3.capture3(env, *command)
+  return if status.success?
+
+  warn [stdout, stderr].reject(&:empty?).join("\n")
+  raise "Command failed (#{status.exitstatus}): #{command.first}"
+end
+
+config = YAML.safe_load_file(ROOT.join("case.yml"), permitted_classes: [],
+                             permitted_symbols: [], aliases: false)
+openscad = executable("OPENSCAD", "openscad")
+blender = executable("BLENDER", "blender")
+abort "OpenSCAD not found; install it or set OPENSCAD" unless openscad
+abort "Blender not found; install it or set BLENDER" unless blender
+
+parameters = config.fetch("parameters").merge(
+  "extra_cutouts" => config.fetch("resolved").fetch("extra_cutouts")
+)
+parts = %w[body lid] + config.fetch("outputs").fetch("coupons")
+buttons = %w[button_a button_b button_c button_reset]
+if parameters["top_profile"] == "oled128x64" &&
+   buttons.any? { |name| parameters[name] }
+  parts << "buttons"
+end
+
+stage = Pathname(Dir.mktmpdir(".rebuild-", ROOT.to_s))
+begin
+  exports = stage.join("exports")
+  previews = stage.join("previews")
+  scratch = stage.join("meshes")
+  FileUtils.mkdir_p([exports, previews, scratch])
+  model = ROOT.join("source/feather_case.scad")
+  renderer = ROOT.join("source/render_stl_previews.py")
+
+  export = lambda do |output, part, overrides = {}|
+    values = parameters.merge(overrides).merge("part" => part)
+    command = [openscad, "-o", output.to_s]
+    values.each { |name, value| command.concat(["-D", "#{name}=#{literal(value)}"]) }
+    run!(*command, model.to_s)
+  end
+
+  config.fetch("outputs").fetch("formats").each do |format|
+    directory = exports.join(format)
+    FileUtils.mkdir_p(directory)
+    parts.each do |part|
+      puts "Exporting #{part}.#{format}…"
+      export.call(directory.join("#{part}.#{format}"), part)
+    end
+  end
+
+  assembly = scratch.join("assembly.stl")
+  puts "Preparing assembly preview…"
+  export.call(assembly, "assembly",
+              "exploded_view" => config.fetch("outputs").fetch("assembly_exploded_view"),
+              "show_references" => false)
+  render_env = {"DISPLAY" => nil, "WAYLAND_DISPLAY" => nil}
+  run!(blender, "--background", "-noaudio", "--python", renderer.to_s, "--",
+       assembly.to_s, previews.to_s, "assembly", env: render_env)
+  parts.each do |part|
+    puts "Rendering #{part} preview…"
+    mesh = scratch.join("#{part}.stl")
+    export.call(mesh, part) unless mesh.file?
+    run!(blender, "--background", "-noaudio", "--python", renderer.to_s, "--",
+         mesh.to_s, previews.to_s, part, "iso", env: render_env)
+  end
+
+  backup = ROOT.join(".build-old-#{Process.pid}")
+  FileUtils.mkdir_p(backup)
+  %w[exports previews].each do |name|
+    current = ROOT.join(name)
+    FileUtils.mv(current, backup.join(name)) if current.exist?
+  end
+  begin
+    FileUtils.mv(exports, ROOT.join("exports"))
+    FileUtils.mv(previews, ROOT.join("previews"))
+    FileUtils.rm_rf(backup)
+  rescue StandardError
+    FileUtils.rm_rf(ROOT.join("exports"))
+    FileUtils.rm_rf(ROOT.join("previews"))
+    %w[exports previews].each do |name|
+      saved = backup.join(name)
+      FileUtils.mv(saved, ROOT.join(name)) if saved.exist?
+    end
+    raise
+  end
+  puts "Rebuilt #{ROOT}"
+ensure
+  FileUtils.rm_rf(stage)
+end

test/config_test.rb

@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+require_relative "test_helper"
+
+class ConfigTest < Minitest::Test
+  def config
+    FeatherCaseWizard::Config.create(name: "Bench GPS", slug: "bench-gps")
+  end
+
+  def test_default_case_has_expected_parts_and_dimensions
+    assert_equal %w[body lid], config.printable_parts
+    assert_in_delta 60.8, config.dimensions["length"], 0.01
+    assert_in_delta 41.66, config.dimensions["width"], 0.01
+    assert_equal ["3mf"], config.outputs["formats"]
+  end
+
+  def test_oled_buttons_and_selected_coupons_are_printable
+    subject = config
+    subject.parameters["top_profile"] = "oled128x64"
+    subject.parameters["button_a"] = false
+    subject.parameters["button_b"] = true
+    subject.outputs["coupons"] = %w[fit_coupon]
+
+    assert_equal %w[body lid buttons fit_coupon], subject.printable_parts
+  end
+
+  def test_wall_local_cutouts_map_to_model_coordinates
+    subject = config
+    length = subject.dimensions["length"]
+    width = subject.dimensions["width"]
+    subject.data["cutouts"] = [
+      cutout("front", 12.0),
+      cutout("rear", 13.0),
+      cutout("left", 14.0),
+      cutout("right", 15.0)
+    ]
+    result = subject.scad_cutouts
+
+    assert_in_delta width - 12.0, result[0][2], 0.001
+    assert_in_delta 13.0, result[1][2], 0.001
+    assert_in_delta 14.0, result[2][2], 0.001
+    assert_in_delta length - 15.0, result[3][2], 0.001
+  end
+
+  def test_cutout_cannot_intersect_floor
+    subject = config
+    subject.data["cutouts"] = [cutout("rear", 12.0).merge("z" => 2.0)]
+
+    error = assert_raises(FeatherCaseWizard::ConfigError) { subject.validate! }
+    assert_match(/floor/, error.message)
+  end
+
+  def test_yaml_round_trip_preserves_resolved_cutouts
+    subject = config
+    subject.data["cutouts"] = [cutout("left", 20.0)]
+
+    Dir.mktmpdir do |directory|
+      path = File.join(directory, "case.yml")
+      File.write(path, subject.to_yaml)
+      loaded = FeatherCaseWizard::Config.load(path)
+      assert_equal subject.data["cutouts"], loaded.data["cutouts"]
+      assert_equal subject.scad_cutouts, loaded.data.dig("resolved", "extra_cutouts")
+    end
+  end
+
+  def test_unsafe_yaml_is_rejected
+    Dir.mktmpdir do |directory|
+      path = File.join(directory, "case.yml")
+      File.write(path, "--- !ruby/object:Object {}\n")
+      assert_raises(FeatherCaseWizard::ConfigError) do
+        FeatherCaseWizard::Config.load(path)
+      end
+    end
+  end
+
+  private
+
+  def cutout(face, horizontal)
+    {
+      "name" => "#{face}-cable",
+      "face" => face,
+      "shape" => "roundrect",
+      "horizontal" => horizontal,
+      "z" => 12.0,
+      "width" => 6.0,
+      "height" => 4.0,
+      "radius" => 1.0
+    }
+  end
+end

test/package_builder_test.rb

@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+require_relative "test_helper"
+
+class PackageBuilderTest < Minitest::Test
+  def test_builds_self_contained_package_and_preserves_history
+    Dir.mktmpdir do |directory|
+      root = Pathname(directory)
+      tools = create_fake_tools(root)
+      model = root.join("model.scad")
+      renderer = root.join("renderer.py")
+      File.write(model, "cube([1,1,1]);\n")
+      File.write(renderer, "# test renderer\n")
+      config = FeatherCaseWizard::Config.create(name: "OLED Demo", slug: "oled-demo")
+      config.parameters["top_profile"] = "oled128x64"
+      config.outputs["formats"] = %w[3mf stl]
+      config.outputs["coupons"] = %w[fit_coupon]
+
+      destination = build(config, root.join("cases"), tools, model, renderer)
+
+      assert destination.join("case.yml").file?
+      assert destination.join("parameters.json").file?
+      assert destination.join("build.rb").executable?
+      %w[body lid buttons fit_coupon].each do |part|
+        assert destination.join("exports/stl/#{part}.stl").file?
+        assert destination.join("exports/3mf/#{part}.3mf").file?
+        assert destination.join("previews/#{part}_iso.png").file?
+      end
+      %w[iso front back left right top].each do |view|
+        assert destination.join("previews/assembly_#{view}.png").file?
+      end
+
+      config.parameters["button_reset"] = true
+      build(config, root.join("cases"), tools, model, renderer)
+      assert_equal 1, Dir.glob(destination.join("history/case-*.yml")).length
+    end
+  end
+
+  def test_failed_build_leaves_existing_package_untouched
+    Dir.mktmpdir do |directory|
+      root = Pathname(directory)
+      destination = root.join("cases/demo")
+      FileUtils.mkdir_p(destination)
+      File.write(destination.join("sentinel"), "keep")
+      model = root.join("model.scad")
+      renderer = root.join("renderer.py")
+      File.write(model, "cube(1);\n")
+      File.write(renderer, "# renderer\n")
+      failing = Class.new do
+        attr_reader :openscad, :blender
+        def initialize
+          @openscad = @blender = "/fake"
+        end
+        def check! = self
+        def run!(*)
+          raise FeatherCaseWizard::ToolError, "planned failure"
+        end
+      end.new
+      config = FeatherCaseWizard::Config.create(name: "Demo", slug: "demo")
+
+      assert_raises(FeatherCaseWizard::ToolError) do
+        FeatherCaseWizard::PackageBuilder.new(
+          config, root: root.join("cases"), toolchain: failing,
+          model_source: model, renderer_source: renderer
+        ).build!
+      end
+      assert_equal "keep", destination.join("sentinel").read
+    end
+  end
+
+  private
+
+  def build(config, root, tools, model, renderer)
+    FeatherCaseWizard::PackageBuilder.new(
+      config, root: root, toolchain: tools,
+      model_source: model, renderer_source: renderer
+    ).build!
+  end
+
+  def create_fake_tools(root)
+    bin = root.join("bin")
+    FileUtils.mkdir_p(bin)
+    openscad = bin.join("openscad")
+    blender = bin.join("blender")
+    File.write(openscad, <<~RUBY)
+      #!/usr/bin/env ruby
+      output = ARGV[ARGV.index("-o") + 1]
+      require "fileutils"
+      FileUtils.mkdir_p(File.dirname(output))
+      File.binwrite(output, "mesh")
+    RUBY
+    File.write(blender, <<~RUBY)
+      #!/usr/bin/env ruby
+      require "fileutils"
+      args = ARGV[(ARGV.index("--") + 1)..]
+      _mesh, output, basename, selected = args
+      views = selected ? selected.split(",") : %w[iso front back left right top]
+      FileUtils.mkdir_p(output)
+      views.each { |view| File.binwrite(File.join(output, "\#{basename}_\#{view}.png"), "png") }
+    RUBY
+    FileUtils.chmod(0o755, [openscad, blender])
+    FeatherCaseWizard::Toolchain.new(
+      env: {"PATH" => bin.to_s, "OPENSCAD" => openscad.to_s, "BLENDER" => blender.to_s}
+    )
+  end
+end

test/test_helper.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require "minitest/autorun"
+require "tmpdir"
+
+require_relative "../lib/feather_case_wizard"
+

test/toolchain_test.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require_relative "test_helper"
+
+class ToolchainTest < Minitest::Test
+  def test_reports_both_missing_dependencies
+    toolchain = FeatherCaseWizard::Toolchain.new(env: {"PATH" => ""})
+    error = assert_raises(FeatherCaseWizard::ToolError) { toolchain.check! }
+
+    assert_match(/OpenSCAD/, error.message)
+    assert_match(/Blender/, error.message)
+    assert_match(/apt-get/, error.message)
+  end
+
+  def test_environment_overrides_are_used
+    Dir.mktmpdir do |directory|
+      executable = File.join(directory, "tool")
+      File.write(executable, "#!/bin/sh\nexit 0\n")
+      FileUtils.chmod(0o755, executable)
+      toolchain = FeatherCaseWizard::Toolchain.new(
+        env: {"PATH" => "", "OPENSCAD" => executable, "BLENDER" => executable}
+      )
+
+      assert_equal executable, toolchain.openscad
+      assert_equal executable, toolchain.blender
+      assert_same toolchain, toolchain.check!
+    end
+  end
+end
+

test/wizard_test.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require "stringio"
+require_relative "test_helper"
+
+class WizardTest < Minitest::Test
+  def test_minimal_new_case_flow_and_confirmation
+    input = StringIO.new(
+      "Demo Case\n" \
+      "\n" \
+      "1\n" \
+      "1\n" \
+      "\n" \
+      "n\n" \
+      "n\n" \
+      "n\n" \
+      "1\n" \
+      "n\n" \
+      "n\n" \
+      "n\n" \
+      "n\n" \
+      "y\n"
+    )
+    output = StringIO.new
+    wizard = FeatherCaseWizard::Wizard.new(ui: HighLine.new(input, output))
+
+    config = wizard.create
+
+    assert wizard.confirm_build(config)
+    assert_equal "demo-case", config.slug
+    assert_equal ["3mf"], config.outputs["formats"]
+    assert_equal %w[body lid], config.printable_parts
+  end
+end

tools/render_stl_previews.py

@@ -0,0 +1,127 @@
+"""Render six inspection views of an STL using Blender.
+
+Usage:
+    blender --background --python tools/render_stl_previews.py -- \
+        input.stl output-directory basename [comma-separated-views]
+"""
+
+import os
+import sys
+
+import bpy
+from mathutils import Vector
+
+
+def arguments():
+    args = sys.argv[sys.argv.index("--") + 1 :]
+    if len(args) not in (3, 4):
+        raise SystemExit(
+            "expected: input.stl output-directory basename [comma-separated-views]"
+        )
+    requested_views = args[3].split(",") if len(args) == 4 else None
+    return args[0], args[1], args[2], requested_views
+
+
+def look_at(camera, target):
+    direction = Vector(target) - camera.location
+    camera.rotation_euler = direction.to_track_quat("-Z", "Y").to_euler()
+
+
+def render_view(camera, center, span, name, direction, output_dir, basename):
+    distance = span * 2.2
+    camera.location = Vector(center) + Vector(direction).normalized() * distance
+    look_at(camera, center)
+    camera.data.type = "ORTHO"
+    camera.data.ortho_scale = span * 1.35
+    bpy.context.scene.render.filepath = os.path.join(
+        output_dir, f"{basename}_{name}.png"
+    )
+    bpy.ops.render.render(write_still=True)
+
+
+def main():
+    input_path, output_dir, basename, requested_views = arguments()
+    os.makedirs(output_dir, exist_ok=True)
+
+    bpy.ops.wm.read_factory_settings(use_empty=True)
+    bpy.ops.wm.stl_import(filepath=os.path.abspath(input_path))
+    model = bpy.context.selected_objects[0]
+    model.name = "Feather case"
+
+    material = bpy.data.materials.new("Case material")
+    material.diffuse_color = (0.16, 0.42, 0.72, 1.0)
+    material.metallic = 0.0
+    material.roughness = 0.45
+    model.data.materials.append(material)
+
+    corners = [model.matrix_world @ Vector(corner) for corner in model.bound_box]
+    mins = Vector([min(v[i] for v in corners) for i in range(3)])
+    maxs = Vector([max(v[i] for v in corners) for i in range(3)])
+    center = (mins + maxs) / 2
+    span = max(maxs - mins)
+
+    world = bpy.data.worlds.new("Inspection world")
+    world.use_nodes = True
+    world.node_tree.nodes["Background"].inputs["Color"].default_value = (
+        0.035,
+        0.04,
+        0.05,
+        1,
+    )
+    world.node_tree.nodes["Background"].inputs["Strength"].default_value = 0.5
+    bpy.context.scene.world = world
+
+    camera_data = bpy.data.cameras.new("Camera")
+    camera = bpy.data.objects.new("Camera", camera_data)
+    bpy.context.collection.objects.link(camera)
+    bpy.context.scene.camera = camera
+
+    key_data = bpy.data.lights.new("Key", type="AREA")
+    key_data.energy = 900
+    key_data.shape = "DISK"
+    key_data.size = span
+    key = bpy.data.objects.new("Key", key_data)
+    key.location = center + Vector((span, -span, span * 1.5))
+    bpy.context.collection.objects.link(key)
+
+    fill_data = bpy.data.lights.new("Fill", type="AREA")
+    fill_data.energy = 500
+    fill_data.size = span
+    fill = bpy.data.objects.new("Fill", fill_data)
+    fill.location = center + Vector((-span, span, span))
+    bpy.context.collection.objects.link(fill)
+
+    scene = bpy.context.scene
+    scene.render.engine = "BLENDER_WORKBENCH"
+    scene.render.resolution_x = 800
+    scene.render.resolution_y = 600
+    scene.render.resolution_percentage = 100
+    scene.render.image_settings.file_format = "PNG"
+    scene.render.film_transparent = False
+    scene.display.shading.light = "STUDIO"
+    scene.display.shading.color_type = "MATERIAL"
+    scene.display.shading.show_shadows = True
+    scene.display.shading.show_cavity = True
+    scene.display.shading.cavity_type = "BOTH"
+    scene.display.shading.curvature_ridge_factor = 1.5
+    scene.display.shading.curvature_valley_factor = 1.2
+
+    views = {
+        "iso": (1, -1, 0.8),
+        "front": (-1, 0, 0),
+        "back": (1, 0, 0),
+        "left": (0, -1, 0),
+        "right": (0, 1, 0),
+        "top": (0, 0, 1),
+    }
+    selected = requested_views or list(views)
+    unknown = sorted(set(selected) - set(views))
+    if unknown:
+        raise SystemExit(f"unknown views: {', '.join(unknown)}")
+    for name in selected:
+        direction = views[name]
+        render_view(camera, center, span, name, direction, output_dir, basename)
+
+
+if __name__ == "__main__":
+    main()