fascat 
pipx install fascat

pip

pip install fascat

The base installation does not require a C++ compiler on Windows.

glTF Meshopt Compression

pip install 'fascat[meshopt]'

The meshopt extra enables EXT_meshopt_compression export. Its meshoptimizer backend is built from C++ source, so Windows users installing this extra need Microsoft C++ Build Tools. Ordinary glTF/GLB export works without it.

KTX2 Preview Decode

pip install 'fascat[ktx2]'

The ktx2 extra installs the Python KTX2 decoder used by browser preview validation when KHR_texture_basisu textures are present; it supports Python 3.11+ on Linux/Windows x86_64. Base installs do not pull the decoder — without the extra, Fascat falls back to glTF Transform plus KTX-Software when those external tools are installed.

UV Unwrap Backend

pip install 'fascat[unwrap]'

The unwrap extra installs xatlas for uv0="unwrap", uv1="unwrap", lightmap UV packing, and bake UV generation.

glTF Compression Tooling

Draco export requires the glTF Transform CLI on PATH, or a FASCAT_GLTF_TRANSFORM environment variable pointing at the executable.

KTX2/Basis texture export requires Node.js plus these packages installed in the working directory, or in FASCAT_NODE_MODULE_ROOT: 

npm install --save-dev @gltf-transform/core @gltf-transform/extensions ktx2-encoder sharp

PyPI

Latest release: pypi.org/project/fascat

Verify

fascat version