It's called procedural geometry.

There are two tactics: Scripting and GUI parametric modeling.

In the GUI version, you model pretty much as always, but instead of recording the resulting geometry, it records the steps you took. You can go back to earlier steps and alter the parameters. You can then grab the steps and make macros out of them to define a prop. You can then export one or more props for use in other apps, such as Poser. I found a free one a while back but I didn't play with it too much.

http://www.k-3d.org/

I have dabbled with Python scripted procedural geometry directly in Poser. I have not finished the kit, and it needs a GUI, but I was able to do quite a lot of stuff.

Have a look here:

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3545388&ebot_calc_page#message_3545388

This room is 100% procedural geometry and shaders. (Not the furniture - the room.)

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