looking for a linux compatible lego design prog.

anyone know a decent one? basically, i dont feel like learning blender just to make mockup mechanical drawings, and my needs are rudimentary enough that the typical lego blocks would suffice (of course, including things like wheels, springs, whatever).

on the other hand, if anybody knows of something that would better serve my purpose, do tell. lego is just the first thing that came to mind.

for further context, im working on mocking up a custom go-cart chassis, and want to see it in 3D, not just pencil/paper.