[r139 BUG?] `raycaster.intersectObject` fails because groupMaterial index is -1 in imported FBX model

[trusktr]

Could FBXLoader issues be the cause of this too?

Wrong material (wrong color) renderer bug?

@Mugen87 @Chaser_Code My hunch is this has to do with the fact that the imported FBX models have, for example, arrays of materials for mesh.material, not just a single material, and that this is somehow confusing WebGLRenderer state.

@looeee

I was having to tediously check each fix against 50 or so models

Do you have those tests? I could add them as e2e tests in the three.js repo.