adjust the stand a bit

script/render_previews.py

@@ -4,6 +4,7 @@ Usage: blender --background --python script/render_previews.py -- model.3mf outp
 """
 
 import math
+import argparse
 import os
 import sys
 import zipfile
@@ -13,12 +14,15 @@ import bpy
 from mathutils import Vector
 
 
-def args():
-    marker = sys.argv.index("--")
-    return os.path.abspath(sys.argv[marker + 1]), os.path.abspath(sys.argv[marker + 2])
-
-
-source, output = args()
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument("source")
+parser.add_argument("output")
+parser.add_argument("--moon", help="Existing Moon 3MF to show on the stand, without modifying it")
+parser.add_argument("--moon-center-z", type=float, default=0.0)
+parser.add_argument("--focus", nargs=3, type=float, help="Center a detail view at X Y Z")
+parser.add_argument("--span", type=float, help="Detail-view span in millimeters")
+options = parser.parse_args(sys.argv[sys.argv.index("--") + 1:])
+source, output = os.path.abspath(options.source), os.path.abspath(options.output)
 os.makedirs(output, exist_ok=True)
 bpy.ops.object.select_all(action="SELECT")
 bpy.ops.object.delete(use_global=False)
@@ -37,6 +41,7 @@ def import_3mf(path):
             material = bpy.data.materials.new(base.attrib.get("name", "material"))
             material.diffuse_color = rgba
             materials.append(material)
+    imported = []
     for element in root.findall("m:resources/m:object", namespace):
         mesh_node = element.find("m:mesh", namespace)
         if mesh_node is None:
@@ -50,11 +55,17 @@ def import_3mf(path):
         data.update()
         obj = bpy.data.objects.new(element.attrib.get("name", "object"), data)
         bpy.context.collection.objects.link(obj)
+        imported.append(obj)
         if materials and "pindex" in element.attrib:
             obj.data.materials.append(materials[int(element.attrib["pindex"])])
+    return imported
 
 
 import_3mf(source)
+if options.moon:
+    for obj in import_3mf(options.moon):
+        obj.location.z += options.moon_center_z
+bpy.context.view_layer.update()
 
 objects = [obj for obj in bpy.context.scene.objects if obj.type == "MESH"]
 if not objects:
@@ -67,6 +78,10 @@ minimum = Vector((min(p.x for p in corners), min(p.y for p in corners), min(p.z
 maximum = Vector((max(p.x for p in corners), max(p.y for p in corners), max(p.z for p in corners)))
 center = (minimum + maximum) / 2
 extent = max(maximum - minimum)
+if options.focus:
+    center = Vector(options.focus)
+if options.span:
+    extent = options.span
 
 world = bpy.context.scene.world
 world.color = (0.035, 0.035, 0.035)
@@ -86,7 +101,9 @@ camera.data.ortho_scale = extent * 1.25
 
 for energy, direction in [(1800, Vector((1, -1, 2))), (900, Vector((-2, 1, 0.5)) )]:
     light_data = bpy.data.lights.new(name="Area", type="AREA")
-    light_data.energy = energy
+    # Imported coordinates are millimeters; scale light power with distance
+    # squared so large models do not turn into unreadable silhouettes.
+    light_data.energy = energy * extent * extent * 0.1
     light_data.shape = "DISK"
     light_data.size = extent
     light = bpy.data.objects.new(name="Area", object_data=light_data)