feat: initial commit

2026-03-05 22:12:38 +01:00
commit bce762a783
380 changed files with 51955 additions and 0 deletions
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+"""Blender Python script: scene setup for turntable animation (Flamenco).
+
+Performs all scene preparation — STL import, materials, camera, pivot animation,
+compositor — then SAVES the resulting .blend file to <scene_path>.
+
+The saved .blend is then rendered by a separate Flamenco task:
+  blender --background <scene_path> --python turntable_gpu_setup.py -a
+
+Using Blender's native -a (--render-anim) keeps the GPU scene (BVH, textures)
+loaded for ALL frames in one process, avoiding per-frame GPU re-upload overhead.
+
+Usage (from Blender):
+  blender --background --python turntable_setup.py -- \\
+    <stl_path> <frames_dir> <frame_count> <degrees> <width> <height> \\
+    <engine> <samples> <part_colors_json> \\
+    [template_path] [target_collection] [material_library_path] \\
+    [material_map_json] [part_names_ordered_json] [lighting_only] \\
+    [cycles_device] [shadow_catcher] [rotation_x] [rotation_y] [rotation_z] \\
+    [turntable_axis] [bg_color] [transparent_bg] [scene_path] [camera_orbit]
+"""
+import bpy
+import sys
+import os
+import json
+import math
+from mathutils import Vector, Matrix
+
+# ── Colour palette ────────────────────────────────────────────────────────────
+PALETTE_HEX = [
+    "#4C9BE8", "#E85B4C", "#4CBE72", "#E8A84C", "#A04CE8",
+    "#4CD4E8", "#E84CA8", "#7EC850", "#E86B30", "#5088C8",
+]
+
+def _srgb_to_linear(c: int) -> float:
+    v = c / 255.0
+    return v / 12.92 if v <= 0.04045 else ((v + 0.055) / 1.055) ** 2.4
+
+def _hex_to_linear(hex_color: str) -> tuple:
+    h = hex_color.lstrip('#')
+    return (
+        _srgb_to_linear(int(h[0:2], 16)),
+        _srgb_to_linear(int(h[2:4], 16)),
+        _srgb_to_linear(int(h[4:6], 16)),
+        1.0,
+    )
+
+PALETTE_LINEAR = [_hex_to_linear(h) for h in PALETTE_HEX]
+SMOOTH_ANGLE = 30
+
+
+# ── Helpers (kept in sync with turntable_render.py) ──────────────────────────
+
+def _ensure_collection(name: str):
+    if name in bpy.data.collections:
+        return bpy.data.collections[name]
+    col = bpy.data.collections.new(name)
+    bpy.context.scene.collection.children.link(col)
+    return col
+
+
+def _assign_palette_material(part_obj, index):
+    color = PALETTE_LINEAR[index % len(PALETTE_LINEAR)]
+    mat = bpy.data.materials.new(name=f"Part_{index}")
+    mat.use_nodes = True
+    bsdf = mat.node_tree.nodes.get("Principled BSDF")
+    if bsdf:
+        bsdf.inputs["Base Color"].default_value = color
+        bsdf.inputs["Metallic"].default_value = 0.35
+        bsdf.inputs["Roughness"].default_value = 0.40
+        try:
+            bsdf.inputs["Specular IOR Level"].default_value = 0.5
+        except KeyError:
+            pass
+    part_obj.data.materials.clear()
+    part_obj.data.materials.append(mat)
+
+
+def _apply_smooth(part_obj, angle_deg):
+    bpy.context.view_layer.objects.active = part_obj
+    part_obj.select_set(True)
+    if angle_deg > 0:
+        try:
+            bpy.ops.object.shade_smooth_by_angle(angle=math.radians(angle_deg))
+        except AttributeError:
+            bpy.ops.object.shade_smooth()
+            part_obj.data.use_auto_smooth = True
+            part_obj.data.auto_smooth_angle = math.radians(angle_deg)
+    else:
+        bpy.ops.object.shade_flat()
+
+
+import re as _re
+
+
+def _apply_rotation(parts, rx, ry, rz):
+    if not parts or (rx == 0.0 and ry == 0.0 and rz == 0.0):
+        return
+    from mathutils import Euler
+    rot_mat = Euler((math.radians(rx), math.radians(ry), math.radians(rz)), 'XYZ').to_matrix().to_4x4()
+    for p in parts:
+        p.matrix_world = rot_mat @ p.matrix_world
+    bpy.ops.object.select_all(action='DESELECT')
+    for p in parts:
+        p.select_set(True)
+    bpy.context.view_layer.objects.active = parts[0]
+    bpy.ops.object.transform_apply(location=False, rotation=True, scale=False)
+    print(f"[turntable_setup] applied rotation ({rx}°, {ry}°, {rz}°) to {len(parts)} parts")
+
+
+def _axis_rotation(axis: str, degrees: float) -> tuple:
+    rad = math.radians(degrees)
+    if axis == "world_x":
+        return (rad, 0.0, 0.0)
+    elif axis == "world_y":
+        return (0.0, rad, 0.0)
+    else:
+        return (0.0, 0.0, rad)
+
+
+def _set_fcurves_linear(action):
+    try:
+        for layer in action.layers:
+            for strip in layer.strips:
+                for channelbag in strip.channelbags:
+                    for fc in channelbag.fcurves:
+                        for kp in fc.keyframe_points:
+                            kp.interpolation = 'LINEAR'
+    except AttributeError:
+        for fc in action.fcurves:
+            for kp in fc.keyframe_points:
+                kp.interpolation = 'LINEAR'
+
+
+def _scale_mm_to_m(parts):
+    if not parts:
+        return
+    bpy.ops.object.select_all(action='DESELECT')
+    for p in parts:
+        p.scale = (0.001, 0.001, 0.001)
+        p.location *= 0.001
+        p.select_set(True)
+    bpy.context.view_layer.objects.active = parts[0]
+    bpy.ops.object.transform_apply(scale=True, location=False, rotation=False)
+    print(f"[turntable_setup] scaled {len(parts)} parts mm→m (×0.001)")
+
+
+def _import_stl(stl_file):
+    stl_dir = os.path.dirname(stl_file)
+    stl_stem = os.path.splitext(os.path.basename(stl_file))[0]
+    parts_dir = os.path.join(stl_dir, stl_stem + "_parts")
+    manifest_path = os.path.join(parts_dir, "manifest.json")
+
+    parts = []
+
+    if os.path.isfile(manifest_path):
+        try:
+            with open(manifest_path, "r") as f:
+                manifest = json.loads(f.read())
+            part_entries = manifest.get("parts", [])
+        except Exception as e:
+            print(f"[turntable_setup] WARNING: failed to read manifest: {e}")
+            part_entries = []
+
+        if part_entries:
+            for entry in part_entries:
+                part_file = os.path.join(parts_dir, entry["file"])
+                part_name = entry["name"]
+                if not os.path.isfile(part_file):
+                    print(f"[turntable_setup] WARNING: part STL missing: {part_file}")
+                    continue
+                bpy.ops.object.select_all(action='DESELECT')
+                bpy.ops.wm.stl_import(filepath=part_file)
+                imported = bpy.context.selected_objects
+                if imported:
+                    obj = imported[0]
+                    obj.name = part_name
+                    if obj.data:
+                        obj.data.name = part_name
+                    parts.append(obj)
+
+            if parts:
+                print(f"[turntable_setup] imported {len(parts)} named parts from per-part STLs")
+
+    if not parts:
+        bpy.ops.wm.stl_import(filepath=stl_file)
+        obj = bpy.context.selected_objects[0] if bpy.context.selected_objects else None
+        if obj is None:
+            print(f"ERROR: No objects imported from {stl_file}")
+            sys.exit(1)
+
+        bpy.context.view_layer.objects.active = obj
+        bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')
+        obj.location = (0.0, 0.0, 0.0)
+        bpy.ops.object.mode_set(mode='EDIT')
+        bpy.ops.mesh.separate(type='LOOSE')
+        bpy.ops.object.mode_set(mode='OBJECT')
+        parts = list(bpy.context.selected_objects)
+        print(f"[turntable_setup] fallback: separated into {len(parts)} part(s)")
+        return parts
+
+    all_corners = []
+    for p in parts:
+        all_corners.extend(p.matrix_world @ Vector(c) for c in p.bound_box)
+
+    if all_corners:
+        mins = Vector((min(v.x for v in all_corners),
+                        min(v.y for v in all_corners),
+                        min(v.z for v in all_corners)))
+        maxs = Vector((max(v.x for v in all_corners),
+                        max(v.y for v in all_corners),
+                        max(v.z for v in all_corners)))
+        center = (mins + maxs) * 0.5
+        for p in parts:
+            p.location -= center
+
+    return parts
+
+
+def _resolve_part_name(index, part_obj, part_names_ordered):
+    base_name = _re.sub(r'\.\d{3}$', '', part_obj.name)
+    if part_names_ordered and index < len(part_names_ordered):
+        return part_names_ordered[index]
+    return base_name
+
+
+def _apply_material_library(parts, mat_lib_path, mat_map, part_names_ordered=None):
+    if not mat_lib_path or not os.path.isfile(mat_lib_path):
+        print(f"[turntable_setup] material library not found: {mat_lib_path}")
+        return
+
+    needed = set(mat_map.values())
+    if not needed:
+        return
+
+    appended = {}
+    for mat_name in needed:
+        inner_path = f"{mat_lib_path}/Material/{mat_name}"
+        try:
+            bpy.ops.wm.append(
+                filepath=inner_path,
+                directory=f"{mat_lib_path}/Material/",
+                filename=mat_name,
+                link=False,
+            )
+            if mat_name in bpy.data.materials:
+                appended[mat_name] = bpy.data.materials[mat_name]
+                print(f"[turntable_setup] appended material: {mat_name}")
+            else:
+                print(f"[turntable_setup] WARNING: material '{mat_name}' not found after append")
+        except Exception as exc:
+            print(f"[turntable_setup] WARNING: failed to append material '{mat_name}': {exc}")
+
+    if not appended:
+        return
+
+    assigned_count = 0
+    for i, part in enumerate(parts):
+        base_name = _re.sub(r'\.\d{3}$', '', part.name)
+        part_key = base_name.lower().strip()
+        mat_name = mat_map.get(part_key)
+
+        if not mat_name and part_names_ordered and i < len(part_names_ordered):
+            step_name = part_names_ordered[i]
+            part_key = step_name.lower().strip()
+            mat_name = mat_map.get(part_key)
+
+        if mat_name and mat_name in appended:
+            part.data.materials.clear()
+            part.data.materials.append(appended[mat_name])
+            assigned_count += 1
+            print(f"[turntable_setup] assigned '{mat_name}' to part '{part.name}'")
+
+    print(f"[turntable_setup] material assignment: {assigned_count}/{len(parts)} parts matched")
+
+
+def main():
+    argv = sys.argv
+    args = argv[argv.index("--") + 1:]
+
+    stl_path             = args[0]
+    frames_dir           = args[1]
+    frame_count          = int(args[2])
+    degrees              = int(args[3])
+    width                = int(args[4])
+    height               = int(args[5])
+    engine               = args[6]
+    samples              = int(args[7])
+    part_colors_json     = args[8] if len(args) > 8 else "{}"
+    template_path        = args[9] if len(args) > 9 and args[9] else ""
+    target_collection    = args[10] if len(args) > 10 else "Product"
+    material_library_path = args[11] if len(args) > 11 and args[11] else ""
+    material_map_raw     = args[12] if len(args) > 12 else "{}"
+    part_names_ordered_raw = args[13] if len(args) > 13 else "[]"
+    lighting_only        = args[14] == "1" if len(args) > 14 else False
+    cycles_device        = args[15].lower() if len(args) > 15 else "auto"
+    shadow_catcher       = args[16] == "1" if len(args) > 16 else False
+    rotation_x           = float(args[17]) if len(args) > 17 else 0.0
+    rotation_y           = float(args[18]) if len(args) > 18 else 0.0
+    rotation_z           = float(args[19]) if len(args) > 19 else 0.0
+    turntable_axis       = args[20] if len(args) > 20 else "world_z"
+    bg_color             = args[21] if len(args) > 21 else ""
+    transparent_bg       = args[22] == "1" if len(args) > 22 else False
+    scene_path           = args[23] if len(args) > 23 else os.path.join(os.path.dirname(frames_dir), "scene.blend")
+    camera_orbit         = args[24] != "0" if len(args) > 24 else True
+    noise_threshold_arg          = args[25] if len(args) > 25 else ""
+    denoiser_arg                 = args[26] if len(args) > 26 else ""
+    denoising_input_passes_arg   = args[27] if len(args) > 27 else ""
+    denoising_prefilter_arg      = args[28] if len(args) > 28 else ""
+    denoising_quality_arg        = args[29] if len(args) > 29 else ""
+    denoising_use_gpu_arg        = args[30] if len(args) > 30 else ""
+
+    os.makedirs(frames_dir, exist_ok=True)
+    os.makedirs(os.path.dirname(scene_path), exist_ok=True)
+
+    try:
+        part_colors = json.loads(part_colors_json)
+    except json.JSONDecodeError:
+        part_colors = {}
+
+    try:
+        material_map = json.loads(material_map_raw) if material_map_raw else {}
+    except json.JSONDecodeError:
+        material_map = {}
+
+    try:
+        part_names_ordered = json.loads(part_names_ordered_raw) if part_names_ordered_raw else []
+    except json.JSONDecodeError:
+        part_names_ordered = []
+
+    if template_path and not os.path.isfile(template_path):
+        print(f"[turntable_setup] ERROR: template_path not found: {template_path}")
+        sys.exit(1)
+
+    use_template = bool(template_path)
+
+    print(f"[turntable_setup] engine={engine}, samples={samples}, size={width}x{height}, "
+          f"frames={frame_count}, degrees={degrees}")
+    print(f"[turntable_setup] part_names_ordered: {len(part_names_ordered)} entries")
+    if use_template:
+        print(f"[turntable_setup] template={template_path}, collection={target_collection}, lighting_only={lighting_only}")
+    else:
+        print("[turntable_setup] no template — using factory settings (Mode A)")
+    if material_library_path:
+        print(f"[turntable_setup] material_library={material_library_path}, material_map keys={list(material_map.keys())}")
+
+    # ── SCENE SETUP ──────────────────────────────────────────────────────────
+
+    if use_template:
+        print(f"[turntable_setup] Opening template: {template_path}")
+        bpy.ops.wm.open_mainfile(filepath=template_path)
+
+        target_col = _ensure_collection(target_collection)
+        parts = _import_stl(stl_path)
+        _scale_mm_to_m(parts)
+        _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
+
+        for part in parts:
+            for col in list(part.users_collection):
+                col.objects.unlink(part)
+            target_col.objects.link(part)
+
+        for part in parts:
+            _apply_smooth(part, SMOOTH_ANGLE)
+
+        if material_library_path and material_map:
+            mat_map_lower = {k.lower(): v for k, v in material_map.items()}
+            _apply_material_library(parts, material_library_path, mat_map_lower, part_names_ordered)
+            for i, part in enumerate(parts):
+                if not part.data.materials or len(part.data.materials) == 0:
+                    _assign_palette_material(part, i)
+        else:
+            for i, part in enumerate(parts):
+                step_name = _resolve_part_name(i, part, part_names_ordered)
+                color_hex = part_colors.get(step_name)
+                if not color_hex:
+                    _assign_palette_material(part, i)
+
+        if shadow_catcher:
+            sc_col_name = "Shadowcatcher"
+            sc_obj_name = "Shadowcatcher"
+            for vl in bpy.context.scene.view_layers:
+                def _enable_col_recursive(layer_col):
+                    if layer_col.collection.name == sc_col_name:
+                        layer_col.exclude = False
+                        layer_col.collection.hide_render = False
+                        layer_col.collection.hide_viewport = False
+                        return True
+                    for child in layer_col.children:
+                        if _enable_col_recursive(child):
+                            return True
+                    return False
+                _enable_col_recursive(vl.layer_collection)
+
+            sc_obj = bpy.data.objects.get(sc_obj_name)
+            if sc_obj:
+                all_world_z = []
+                for part in parts:
+                    for corner in part.bound_box:
+                        all_world_z.append((part.matrix_world @ Vector(corner)).z)
+                if all_world_z:
+                    sc_obj.location.z = min(all_world_z)
+                print(f"[turntable_setup] shadow catcher enabled, plane Z={sc_obj.location.z:.4f}")
+            else:
+                print(f"[turntable_setup] WARNING: shadow catcher object '{sc_obj_name}' not found")
+
+        needs_auto_camera = (lighting_only and not shadow_catcher) or not bpy.context.scene.camera
+        if not needs_auto_camera and bpy.context.scene.camera:
+            bpy.context.scene.camera.data.clip_start = 0.001
+
+        print(f"[turntable_setup] template mode: {len(parts)} parts imported into '{target_collection}'")
+
+    else:
+        needs_auto_camera = True
+        bpy.ops.wm.read_factory_settings(use_empty=True)
+
+        parts = _import_stl(stl_path)
+        _scale_mm_to_m(parts)
+        _apply_rotation(parts, rotation_x, rotation_y, rotation_z)
+
+        for i, part in enumerate(parts):
+            _apply_smooth(part, SMOOTH_ANGLE)
+
+        if material_library_path and material_map:
+            mat_map_lower = {k.lower(): v for k, v in material_map.items()}
+            _apply_material_library(parts, material_library_path, mat_map_lower, part_names_ordered)
+            for i, part in enumerate(parts):
+                if not part.data.materials or len(part.data.materials) == 0:
+                    _assign_palette_material(part, i)
+        else:
+            for i, part in enumerate(parts):
+                step_name = _resolve_part_name(i, part, part_names_ordered)
+                color_hex = part_colors.get(step_name)
+                if color_hex:
+                    mat = bpy.data.materials.new(name=f"mat_{part.name}")
+                    mat.use_nodes = True
+                    bsdf = mat.node_tree.nodes.get("Principled BSDF")
+                    if bsdf:
+                        color = _hex_to_linear(color_hex)
+                        bsdf.inputs["Base Color"].default_value = color
+                        bsdf.inputs["Metallic"].default_value = 0.35
+                        bsdf.inputs["Roughness"].default_value = 0.40
+                        try:
+                            bsdf.inputs["Specular IOR Level"].default_value = 0.5
+                        except KeyError:
+                            pass
+                    part.data.materials.clear()
+                    part.data.materials.append(mat)
+                else:
+                    _assign_palette_material(part, i)
+
+    if needs_auto_camera:
+        all_corners = []
+        for part in parts:
+            all_corners.extend(part.matrix_world @ Vector(c) for c in part.bound_box)
+
+        bbox_min = Vector((min(v.x for v in all_corners), min(v.y for v in all_corners), min(v.z for v in all_corners)))
+        bbox_max = Vector((max(v.x for v in all_corners), max(v.y for v in all_corners), max(v.z for v in all_corners)))
+        bbox_center = (bbox_min + bbox_max) * 0.5
+        bbox_dims = bbox_max - bbox_min
+        bsphere_radius = max(bbox_dims.length * 0.5, 0.001)
+
+        print(f"[turntable_setup] bbox_dims={tuple(round(d, 4) for d in bbox_dims)}, bsphere_radius={bsphere_radius:.4f}")
+
+        if not use_template:
+            light_dist = bsphere_radius * 6.0
+            bpy.ops.object.light_add(type='SUN', location=(
+                bbox_center.x + light_dist * 0.5,
+                bbox_center.y - light_dist * 0.35,
+                bbox_center.z + light_dist,
+            ))
+            sun = bpy.context.active_object
+            sun.data.energy = 4.0
+            sun.rotation_euler = (math.radians(45), 0, math.radians(30))
+
+            bpy.ops.object.light_add(type='AREA', location=(
+                bbox_center.x - light_dist * 0.4,
+                bbox_center.y + light_dist * 0.4,
+                bbox_center.z + light_dist * 0.7,
+            ))
+            fill = bpy.context.active_object
+            fill.data.energy = max(800.0, bsphere_radius ** 2 * 2000.0)
+            fill.data.size = max(4.0, bsphere_radius * 4.0)
+
+        cam_dist = bsphere_radius * 2.5
+        cam_location = Vector((bbox_center.x + cam_dist, bbox_center.y, bbox_center.z + bsphere_radius * 0.5))
+        bpy.ops.object.camera_add(location=cam_location)
+        camera = bpy.context.active_object
+        bpy.context.scene.camera = camera
+        camera.data.clip_start = max(cam_dist * 0.001, 0.0001)
+        camera.data.clip_end = cam_dist * 10.0
+
+        empty = bpy.data.objects.new("target", None)
+        bpy.context.collection.objects.link(empty)
+        empty.location = bbox_center
+
+        track = camera.constraints.new(type='TRACK_TO')
+        track.target = empty
+        track.track_axis = 'TRACK_NEGATIVE_Z'
+        track.up_axis = 'UP_Y'
+
+        if not use_template:
+            world = bpy.data.worlds.new("World")
+            bpy.context.scene.world = world
+            world.use_nodes = True
+            bg = world.node_tree.nodes["Background"]
+            bg.inputs["Color"].default_value = (0.96, 0.96, 0.97, 1.0)
+            bg.inputs["Strength"].default_value = 0.15
+
+        pivot = bpy.data.objects.new("pivot", None)
+        bpy.context.collection.objects.link(pivot)
+        pivot.location = bbox_center
+        camera.parent = pivot
+        camera.location = (cam_dist, 0, bsphere_radius * 0.5)
+
+        scene = bpy.context.scene
+        scene.frame_start = 1
+        scene.frame_end = frame_count
+
+        pivot.rotation_euler = (0, 0, 0)
+        pivot.keyframe_insert(data_path="rotation_euler", frame=1)
+        pivot.rotation_euler = _axis_rotation(turntable_axis, degrees)
+        pivot.keyframe_insert(data_path="rotation_euler", frame=frame_count + 1)
+        _set_fcurves_linear(pivot.animation_data.action)
+
+    else:
+        scene = bpy.context.scene
+        scene.frame_start = 1
+        scene.frame_end = frame_count
+
+        all_corners = []
+        for part in parts:
+            all_corners.extend(part.matrix_world @ Vector(c) for c in part.bound_box)
+
+        bbox_center = Vector((
+            (min(v.x for v in all_corners) + max(v.x for v in all_corners)) * 0.5,
+            (min(v.y for v in all_corners) + max(v.y for v in all_corners)) * 0.5,
+            (min(v.z for v in all_corners) + max(v.z for v in all_corners)) * 0.5,
+        ))
+
+        if camera_orbit and bpy.context.scene.camera:
+            # Camera-orbit mode: rotate camera around static product.
+            # Parts stay stationary → Cycles BVH cached across all frames → ~40% speedup.
+            camera = bpy.context.scene.camera
+            cam_world = camera.matrix_world.copy()
+
+            cam_pivot = bpy.data.objects.new("cam_pivot", None)
+            bpy.context.collection.objects.link(cam_pivot)
+            cam_pivot.location = bbox_center
+
+            camera.parent = cam_pivot
+            # Restore world-space transform after parenting (Blender recomputes local matrix)
+            camera.matrix_world = cam_world
+
+            cam_pivot.rotation_euler = (0, 0, 0)
+            cam_pivot.keyframe_insert(data_path="rotation_euler", frame=1)
+            cam_pivot.rotation_euler = _axis_rotation(turntable_axis, degrees)
+            cam_pivot.keyframe_insert(data_path="rotation_euler", frame=frame_count + 1)
+            _set_fcurves_linear(cam_pivot.animation_data.action)
+            print(f"[turntable_setup] camera-orbit mode: cam_pivot at {tuple(round(c, 4) for c in bbox_center)}")
+        else:
+            # Product-rotation mode: parts parent to pivot (default fallback when no camera)
+            pivot = bpy.data.objects.new("turntable_pivot", None)
+            bpy.context.collection.objects.link(pivot)
+            pivot.location = bbox_center
+
+            for part in parts:
+                part.parent = pivot
+
+            pivot.rotation_euler = (0, 0, 0)
+            pivot.keyframe_insert(data_path="rotation_euler", frame=1)
+            pivot.rotation_euler = _axis_rotation(turntable_axis, degrees)
+            pivot.keyframe_insert(data_path="rotation_euler", frame=frame_count + 1)
+            _set_fcurves_linear(pivot.animation_data.action)
+            print(f"[turntable_setup] product-rotation mode: {len(parts)} parts parented to turntable_pivot")
+
+    # ── Colour management ────────────────────────────────────────────────────
+    scene = bpy.context.scene
+    if not use_template:
+        scene.view_settings.view_transform = 'Standard'
+        scene.view_settings.exposure = 0.0
+        scene.view_settings.gamma = 1.0
+        try:
+            scene.view_settings.look = 'None'
+        except Exception:
+            pass
+
+    # ── Render engine ────────────────────────────────────────────────────────
+    if engine == "eevee":
+        eevee_ok = False
+        for eevee_id in ('BLENDER_EEVEE', 'BLENDER_EEVEE_NEXT'):
+            try:
+                scene.render.engine = eevee_id
+                eevee_ok = True
+                print(f"[turntable_setup] EEVEE engine id: {eevee_id}")
+                break
+            except TypeError:
+                continue
+        if eevee_ok:
+            for attr in ('taa_render_samples', 'samples'):
+                try:
+                    setattr(scene.eevee, attr, samples)
+                    break
+                except AttributeError:
+                    continue
+        else:
+            print("[turntable_setup] WARNING: EEVEE not available, falling back to Cycles")
+            engine = "cycles"
+
+    if engine != "eevee":
+        scene.render.engine = 'CYCLES'
+        scene.cycles.samples = samples
+        scene.cycles.use_denoising = True
+        scene.cycles.denoiser = denoiser_arg if denoiser_arg else 'OPENIMAGEDENOISE'
+        if denoising_input_passes_arg:
+            try: scene.cycles.denoising_input_passes = denoising_input_passes_arg
+            except Exception: pass
+        if denoising_prefilter_arg:
+            try: scene.cycles.denoising_prefilter = denoising_prefilter_arg
+            except Exception: pass
+        if denoising_quality_arg:
+            try: scene.cycles.denoising_quality = denoising_quality_arg
+            except Exception: pass
+        if denoising_use_gpu_arg:
+            try: scene.cycles.denoising_use_gpu = (denoising_use_gpu_arg == "1")
+            except AttributeError: pass
+        if noise_threshold_arg:
+            scene.cycles.use_adaptive_sampling = True
+            scene.cycles.adaptive_threshold = float(noise_threshold_arg)
+        if denoiser_arg:
+            scene["_denoiser_override"] = denoiser_arg
+        # scene.cycles.device is set by turntable_gpu_setup.py at render time
+        # (GPU preferences are user-level and not stored in .blend)
+        # We set the intended device here so gpu_setup can read it.
+        scene["_cycles_device"] = cycles_device
+        # Keep BVH, textures, and scene data resident on GPU between frames.
+        # Critical for -a mode: prevents Cycles from re-uploading data each frame.
+        scene.render.use_persistent_data = True
+        # No motion blur needed for static mechanical parts — eliminates per-frame
+        # CPU deformation calculations.
+        scene.render.use_motion_blur = False
+        print(f"[turntable_setup] cycles_device preference saved: {cycles_device}")
+        print("[turntable_setup] use_persistent_data=True, use_motion_blur=False")
+
+    # ── Render output settings ───────────────────────────────────────────────
+    scene.render.resolution_x = width
+    scene.render.resolution_y = height
+    scene.render.resolution_percentage = 100
+    scene.render.image_settings.file_format = 'PNG'
+    # Blender -a appends 4-digit frame number: "frame_" → "frame_0001.png"
+    scene.render.filepath = os.path.join(frames_dir, "frame_")
+
+    # ── Transparent background ────────────────────────────────────────────────
+    # bg_color compositing is done by FFmpeg in the compose-video task.
+    # Blender renders transparent PNG frames (film_transparent=True) when
+    # bg_color is set; FFmpeg then overlays them over a solid colour background.
+    if bg_color or transparent_bg:
+        scene.render.film_transparent = True
+        if bg_color:
+            print(f"[turntable_setup] film_transparent=True for FFmpeg bg_color compositing ({bg_color})")
+        else:
+            print("[turntable_setup] transparent_bg enabled (alpha PNG frames)")
+
+    # ── Save scene ───────────────────────────────────────────────────────────
+    # save_as_mainfile saves to an explicit new path (like File > Save As).
+    # save_mainfile would save back to the originally-opened template path.
+    print(f"[turntable_setup] Saving scene to {scene_path} …")
+    result = bpy.ops.wm.save_as_mainfile(filepath=scene_path)
+    if 'FINISHED' not in result:
+        print(f"[turntable_setup] ERROR: save_as_mainfile returned {result} — aborting")
+        sys.exit(1)
+    if not os.path.isfile(scene_path):
+        print(f"[turntable_setup] ERROR: scene file not found after save: {scene_path}")
+        sys.exit(1)
+    size_mb = os.path.getsize(scene_path) / 1024 / 1024
+    print(f"[turntable_setup] Scene saved → {scene_path} ({size_mb:.1f} MB)")
+    print(f"[turntable_setup] Ready for: blender --background {scene_path} --python turntable_gpu_setup.py -a")
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except SystemExit:
+        raise
+    except Exception as _exc:
+        import traceback
+        traceback.print_exc()
+        print(f"[turntable_setup] FATAL: unhandled exception — {_exc}")
+        sys.exit(1)