Modify indexed BufferGeometry (mouse or input)

Since multimaterial raycast is supported in the core of three.js from revision 94, the workaround of mugen87 is no longer needed.

see also
[SOLVED] Raycaster - MultiMaterial
https://github.com/mrdoob/three.js/pull/14227

On Github corresponding note. https://github.com/hofk/THREEf.js README.md