[Cycle]

Oooh, I found OpenSCAD. I can learn programming languages pretty quickly, and for some reason, my brain likes the idea of using programming to define the objects. And OpenSCAD exports in the formats that Z88 Aurora uses, so after I get the frame mocked up in OpenSCAD, I can test its ability to handle load in Z88 Aurora (or export the model in DXF format from OpenSCAD, then have someone help me to test it in an FEA program, if I still find Z88 Aurora inscrutable).

That gets around my brain's block on putting what it sees into a graphical model, and allows me to alter the model without messing everything up, since it's all defined in code.

{EDIT: Even better, I only have to model half the frame, then mirror it to the opposite side using one line of code. Loving this program.}