Haha, another popular concept, I'm working on something similar
As to the clearances (<- term mostly in the forum)
This also depends on whether it is to be printed as a working piece in one go, or separate pieces clicked together.
My experiences/current working guidelines :
Assuming the Strong & Flexible material, clearances for "moving parts" models (<- see tutorials on this) should be around 0.6 mm, but trial and error is part of the process
If it is to be clicked together after printing you can go at least as low as 0.2 mm. (crudely said : pegs can turn out 0.1 mm larger, holes 0.1mm smaller) But.. trial and error is also the answer here..
Luckily, the Strong an Flexible materials have a tendency to "wear in", usually resulting in smoother movement after a while.
Also keep in mind that larger surface areas need larger gaps.
Good luck !
Oh and POV-Ray rules ! But indeed, it is not suited for meshes.
(It can render them nicely though !)
Stijn