Thanks Michael, I'll check those out. I'd be happy right now if I even had to limit any curved portions to semi-circles in my drawings.

What I ultimately want to do is draw 3 dimensional curves that I convert to g-code to control a machine - a sort of different approach to CAM where I have control over all of the tool paths exactly, rather than having them generated algorithmic-ally like current CAM programs do. Right now I hand code most of my production parts because I need total tool path control. But the drawing tools in Moi3D are freaking awesome, better than CorelDraw even, and I'd like to be able to harness that.