Micheal:

That's precisely why I highlighted the 2 lines in yellow in the attached pic. A triangle is the absolute basic container to describe a plane in 3d space.

I was expecting an "intuitive arc command" to recognize the 2 yellow sets of co-ordinate points, so the arc command would use that data to draw the arc in the correct plane. Any arc in 3d space needs some reference, otherwise its just guessing.

How does the Cplane deal with this attached pic?
Using my "intuitive arc command" analogy above, this is one way I could use to draw arc's
on planes of an inscribed tetrahedron?

So the bottom line is: I need v2?

This beta should be available for input from users, like me, that remember AutoCad v2.5 which came on
5 X 5 1/4 inch floppies, and the agony of trying to draw in 3d :)

thanks! Frenchy, your becoming my shadow! we have to stop meeting like this and elsewhere :)