three.js updating geometry face materialindex

Question

Is there a way to change the materialIndex on a face of an existing Mesh? This isn\'t discussed in the How to Update Things documentation, so I am not sure if it\'s possible

Answer 1

This behavior has changed.

If you are using THREE.Geometry, you can use the following pattern to change a face material index:

mesh.geometry.faces[ 0 ].materialIndex = 1;

If the geometry has been previously-rendered, you must also set

mesh.geometry.groupsNeedUpdate = true;

three.js r.88