FileMeshes override the appearance of their parent BasePart with a custom mesh.

Unlike a MeshPart they do not change the physical properties of the part. Because of this they support assigning FileMesh.MeshId at runtime, which MeshParts cannot.

FileMesh and SpecialMesh instances are slightly slower to update in the rendering engine compared to MeshParts. When possible, you should should prefer using [MeshParts] over FileMesh instances.

Skinning

Our new mesh importer supports importing meshes with skeletal joint. This will be saved in the mesh's asset data.

Named joints defined within a MeshPart's mesh asset data can skin to connected MeshParts with the same name if it also have a mesh that includes a joint with the same name. Parts can be connected directly or indirectly by Motor6Ds, Welds, BallSocketConstraints, HingeConstraints, or other skinning-enabled joints within the same Model.

Mesh joints can also skin to Bone instances that are descendants of connected parts, or connected parts with a FileMesh referencing a skinned mesh.