Initial parametric Feather case generator

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()