Text Based 3D Modeling

I've been playing around with the Google free SketchUp program, and it's pretty nifty, although it takes some practice, and only really seems suited to architecture. Like all other 3D programs, it starts killing my wrists after a while, and I wonder if it might not be sensible to build some sort of text interface to a 3D modeling program. Sort of like POVRay (in which I built a really bitchin', animated version of a steam engine, long ago). But of course POVRay is not realtime. I want something like:

rectangle(10,10) upperJoist;
upperJoist.extend(z, 20);

which would create a block 10x10x20. As far as positioning and putting things together, I think you could take a cue from SketchUp and do intelligent things with endpoints, faces, etc. Hmmm... maybe I just want to download POVRay again.

Update: Such a thing kind of exists - Visual for Python lets you do almost what I say in the post above:

floor = box (pos=(0,0,0), length=4, height=0.5, width=4, color=color.blue)

ball = sphere (pos=(0,4,0), radius=1, color=color.red)

ball.velocity = vector(0,-1,0)

Neat!