glb2cua

Convert glTF / GLB models into Virt-A-Mate CustomUnityAsset (.assetbundle) packages — fully offline, without Unity.

glb2cua is the conversion engine behind CUA Asset Studio. It clones donor objects out of a prebuilt Unity "mold" asset bundle and bakes a fresh prefab straight from the glb's material → texture → channel graph, then writes a clean minimal bundle VAM can load as a CustomUnityAsset atom. Part of the Shadow Venom CRAFT tool line.

• Static path — no skin + no animation → flattened world matrices, MeshFilter + MeshRenderer.
• Animated path — skinned / rigid / hybrid → node tree preserved, per-mesh multi-skin, one DenseClip drives all TRS nodes.

It is a single self-contained script (glb2cua_mold.py) plus the Mold.assetbundle it bakes into.

Want a GUI with live 3D preview, a transform gizmo, and per-material editing? Use CUA Asset Studio, which drives this engine.

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Install

git clone https://github.com/R18SV/glb2cua.git
cd glb2cua
pip install -r requirements.txt

Mold.assetbundle ships in this repo; the script loads it from next to itself by default (override with the MOLD env var).

Usage

# single model
python glb2cua_mold.py <model.glb> [name] [out.assetbundle]

# batch every *.glb in a folder -> <outdir>/<name>.assetbundle + conversion_report.json
python glb2cua_mold.py <folder> [outdir]

# pack many models into ONE bundle with N switchable prefabs
python glb2cua_mold.py --pack <out.assetbundle> <glb|folder> [<glb|folder> ...]

# pack one multi-animation glb -> ONE bundle, one switchable prefab per clip
python glb2cua_mold.py --anims <out.assetbundle> <model.glb>

In VAM, load the resulting .assetbundle on a CustomUnityAsset atom. For --pack / --anims bundles, switch prefabs via the atom's Asset-name dropdown (or a trigger).

Options (environment variables)

All tuning is via env vars, so the engine stays a clean stdin-free CLI (this is exactly how CUA Asset Studio drives it):

Var	Default	Meaning
MOLD	./Mold.assetbundle	Path to the mold bundle baked into.
TARGET_HEIGHT	1.8	Target height in metres (when NORMALIZE=1).
NORMALIZE	1	0 keeps the glb's real size (props / rooms). Static path only.
ORIENT_YAW	0	Root yaw in degrees about Y, baked into vertices. Static path only.
POS_X / POS_Y / POS_Z	0	Root position offset in metres relative to origin.
FORCE_OPAQUE	0	1 forces all materials opaque (fixes glbs that spuriously mark solid surfaces BLEND). Default honors source alphaMode.
TWO_SIDED	off	off / alpha / all — opt-in double-siding.
VERTEX_COLOR	0	1 uses the mold's unlit vertex-colour shader and writes COLOR_0 (for texture-less, vertex-coloured models).
COLLIDER	none	none / box (AABB) / convex (per-mesh hull) / mesh (exact, physics-heavy).
ANIM_INDEX	0	Which glb clip to bake on the single path (all clips listed in the report).
PINGPONG	0	1 bakes forward+reverse so the loop's end frame equals its start (no snap-back).
TEX_AUX_MAX / TEX_SLIM	0 / –	Downscale texture slots at bake time. TEX_SLIM is a set of normal / spec / albedo.
SMOOTHNESS_MAX / METALLIC_BOOST	0.7 / 1.0	Global smoothness cap / metallic multiplier.
OVERRIDES	–	Path to a JSON file of per-material overrides (see below).
GC	1	0 skips garbage-collecting mold residue (debug).

Per-material overrides (OVERRIDES)

{ "materials": {
  "<material name | index>": {
    "mode": "opaque|cutout|fade", "metallic": 0.0, "smoothness": 0.5,
    "color": "#ffffff", "emission": "#000000", "emissionIntensity": 1.0,
    "cutoff": 0.5, "normalScale": 1.0, "twoSided": false
  }
}}

Values are layered on top of the glb-read material values; mode wins over FORCE_OPAQUE.

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Building a standalone exe (optional)

A frozen single-folder build lets end users run the engine without a Python install. glb2cua.spec is included:

pip install pyinstaller
pyinstaller --noconfirm glb2cua.spec
# -> dist/glb2cua/glb2cua.exe

The spec collect_alls UnityPy and the texture codecs (etcpak / texture2ddecoder / astc_encoder) plus fmod_toolkit + pyfmodex (UnityPy loads these transitively even for mesh/texture-only work).

How it relates to CUA Asset Studio

CUA Asset Studio shells out to this engine, passing the options above as env vars and the glb / output as arguments. The GUI's live three.js preview mirrors the same placement maths (centre on floor, normalize, yaw, position) so what you see is what gets baked.

License

MIT © 2026 Shadow Venom (R18SV)

Virt-A-Mate is a trademark of its respective owner. This project is an independent community tool and is not affiliated with or endorsed by Virt-A-Mate.