Sketchfab supports a maximum of 100 unique materials in a single 3D scene.
The number of materials in a model is a huge factor in the speed of the viewer, and going beyond 100 materials quickly slows down the model load time and it's rendering performance.
If we detect more than 100 materials during processing, we first attempt to merge identical materials. We consider "identical materials" to be materials that have different names but otherwise exactly the same properties.
If there are still more than 100 materials, we then "clamp" to 100, using a series of rules to decide which materials to keep. The priority for preserving materials is:
- Materials with textures; the more channels that have a texture, the higher the priority
- Materials used by the highest number of separate geometries (i.e. meshes or objects)
- Materials used on the largest surface area (for objects with faces)
- Materials used by the highest number of vertices (for point clouds and lines)
The lowest priority materials beyond the maximum 100 will be merged into a single material. This 100th material will be shown as a default white color across all the parts of the model that used materials we removed.