In Eevee/Cycles, if a face has a material index that is higher than the highest material slot, the last material slot is used (empty or not). Since faces can get invalid material indices through common operations like Boolean modifier, this shouldn't stop the renderer.
I think this fixes #692
In Eevee/Cycles, if a face has a material index that is higher than the highest material slot, the last material slot is used (empty or not). Since faces can get invalid material indices through common operations like Boolean modifier, this shouldn't stop the renderer.