I'm using V26 and doing mostly 2D, but definitely some 3D toolpaths. I've attached an example of a part where I'd really like to toolpath just the ring, but when I select inner and outer boundaries, it still calculates the toolpath across the entire middle surface. I use mostly planar and z-level finishing, as equidistant usually chokes my machine. The boundary issue only seems to manifest itself on finishing toolpaths - the roughing algorithms calculate as I'd expect.

I've tried selecting just the 'bottom' surfaces as machining faces, and tried selecting ALL, and using boundaries to limit the toolpath. It doesn't seem to make a difference.

Can anyone either shed some light on this workflow, or point me in another direction to do accomplish the goal?

I've attached one sample part, and one real one for kicks. Any help appreciated.
Todd