Can i turn off parts of a single object when they are outside of the frustrum ?
Suppose i have this one giant object, with 20k polys in order to get only one draw call (similar to zombieville USA). Is there any way that i can tell unity to ignore specific bone hierarchies and the related skinned geometry to reduce the poly count in the frustrum ?
No, an object is either visible or it's not, so either all the geometry is submitted or none of it is. However, OpenGL itself won't draw triangles that are outside the frustrum, and the PowerVR chip won't draw triangles that are fully occluded. So just because, say, 10K tris are submitted, doesn't mean 10K tris are drawn. (But there is no way to get this info...Unity can only tell you about the geometry being submitted.)