@zletaris The error you post comes from the Unity import setting "Optimize Game Object" (see attached image). Whe you switch that on, Unity will do some magic stuff with the bones and hide them from the Editor and from your/my code. I find the latter is very annoying, because it causes this error. Just switch it off and you're ok. @duencil That is exactly how SimpleLOD works. You can't specify any target nr of vertices, only error tolerances.