You can assign multiple materials to a single mesh in an FBX file. This allows you to create objects that have different visual elements. For example, consider a skateboard object that has one material for the deck, another material for the trucks, and a third material for the wheels, all without using multiple meshes.

For more information about how to use materials, see Materials Guidance and Reference for Custom Models.

You can assign materials to the faces of the mesh in the DCC tool of your choice. When the mesh is imported into Horizon, a material slot is created for each material on the mesh. You can reference these slots by name or index, where the first material is in slot 0.

When the order of material slots is important, Horizon uses the same naming convention as Unreal Engine. Add a suffix of “_skin##” on the material name to define which slot it belongs in. For example, Metal_skin00 would appear in slot 0 and Wood_skin01 would appear in slot 1. The same slot number cannot be used twice and the slot number cannot be greater than or equal to the number of materials.

You can reference material slots either by name or index. When you use indexes for material slots, index 0 represents the first material. Meshes with a single material always use material slot 0.

If you don’t specify a material slot, then the setMaterial function (including for Unity Asset Bundles) will set the material in slot 0. To set a material in a different material slot, refer to the slot by name or index.

The setTexture function sets the texture for the entire mesh.

Modifying tintColor or tintStrength in the EntityStyle affects the entire mesh.

When using multiple materials, masked materials and vertex texture color shading models have the following limitations: