Hi Michael.

You can make it simpler than in Rhino. I think all you need are movable planes that the user can move and place freely. Then keep them in a list (or maby better: small, undisturbing thumbnails that also show the orientaton of each plane all the time), so the user can jump to the preferred plane. The origin of the plane and its x direction should be visable i guess. I imagine a small gray or blue transparent rectangle as a good cPlane object.

- Fredrik