evo-threejs-scene-parser

evo-threejs-scene-parser

Parses a Three.js scene file (one that exports a createScene() function) using a headless Node.js runtime, then exports each part as Wavefront OBJ files in two views:

• part_meshes/<part_name>/<mesh_name>.obj — one OBJ per direct child Mesh of each Group
• links/<part_name>.obj — merged OBJ of all direct child meshes of the Group (NOT nested sub-group descendants)

Output Layout

output/
├── part_meshes/
│   ├── <part_name>/<mesh_name>.obj  # one per direct child Mesh
│   └── ...
└── links/
    ├── <part_name>.obj  # merged direct child meshes only
    └── ...

Part Identification Rules

1. A "part" is ANY THREE.Group found anywhere in the scene tree (excluding the root). Use root.traverse() and collect node.isGroup.
2. Standalone Meshes that are direct children of the root (not inside any Group) are also exported as their own part.
3. For each Group:
   • Direct child Meshes go to part_meshes/<group.name>/<mesh.name>.obj
   • Direct child Meshes are merged (with world transforms baked) → links/<group.name>.obj
   • Nested sub-groups are treated as SEPARATE parts (not included in parent's link)
4. root.updateMatrixWorld(true) MUST be called before export so world matrices are baked.
5. Use node.name for naming; fallback UnnamedGroup_<i> / UnnamedMesh_<i>.
6. For merging: clone geometries, apply matrixWorld, convert indexed→non-indexed, strip non-essential attributes (keep only position+normal), then use mergeGeometries().

Usage (Python)

import sys
sys.path.insert(0, '/app/environment/skills/evo-threejs-scene-parser/scripts')
from run import run_threejs_parser
result = run_threejs_parser('/root/data/object.js', '/root/output')
print(result)

Usage (CLI)

cd /root && node /app/environment/skills/evo-threejs-scene-parser/scripts/parser.mjs /root/data/object.js /root/output

Key Implementation Notes

• Polyfill global.self, global.window, global.document for headless Three.js addons.
• Import paths: three, three/examples/jsm/exporters/OBJExporter.js, three/examples/jsm/utils/BufferGeometryUtils.js.
• Three.js v0.170.0: use mergeGeometries (not mergeBufferGeometries), BufferGeometry only.
• Sanitize file names with [^A-Za-z0-9_.-]+ → _.
• For links: merge only DIRECT child meshes of each group, not descendants from nested sub-groups.