Formats and compatibility

Loose MaterialX

A .mtlx file is XML. Referenced textures and libraries typically live beside it. A browser file picker cannot grant access to arbitrary sibling resources; use a portable package or a hosted URL when the material has dependencies.

Material packages

A .mtlx.zip is an ordinary zip containing a MaterialX document and its resources. The package model unifies loose and packaged input. Archives are inspected before use and resource references resolve within the package.

Geometry and environments

Preview models use glTF/GLB. The material source is still MaterialX. Environments accept equirectangular HDR, EXR, PNG, and JPEG. Neutral studio lighting is generated in HDR; photographs are optional rather than required for startup.

Validation versus rendering

XML parsing, semantic validation, dependency checks, renderer support checks, and shader compilation are separate stages. A structurally valid document may use constructs unsupported by the current preview backend. Use the viewer's inspection and log panels to distinguish those cases.

The renderer uses Three.js WebGPU with a WebGL2 fallback. MaterialX translation follows the supported Three.js MaterialX path; not all MaterialX extensions or rendering features are implemented.