Masking geometry without breaking constraints/parents It is common to use simple geometry for physics simulations, and then parent more advanced geometry to it to be rendered. Normally this simple geometry is on another layer. However, I have a case where the simmed geometry is on the main render layer and part of an object that needs to be rendered (because it's all one piece brought in with a mesh cache.) Separating any verts out isn't an option as it would break the cache.

I need to mask out some of this geometry, but I have empties parented to it and bones constrained to it as part of my rig. If I use the mask modifier, these break as the vertices are missing. I can put a transparent shader on it, but this still costs render time and produces artifacts at intersection.

Is there any other way I can get these verts to not render?
If you are using cycle ...

You can turn off certain types of ray visibility for individual objects and the camera will ignore them. 

NOTE
If this question is more complex than it seems I advice you to upload more images and even a portion of the .blend file so someone could download and dissect the problem.