The simplicity principle can't be so obvious. This principle rely on the fact that 3d programs are suposed to help us not to upset us. This is where Raylab fails. Indeed its language is simple, you may get a liltle while to get used to it but after that, everything becomes automatic. But to model complex objects using Raylab is a heavy analitic geometry exercise and more complicated than using nurbs or polygons. Comercial programs, of course, are better in this area. Rhinoceros, 3D amx, Real 3D, Blender, etc are very pratic for modeling. But even then there are some trick problems. Some texture and complex modeling could get o lot of unnecessary work. Get a good texture in Blender is a resignation pratice, using 3D max can be easier but takes a while to do it fast and do it right (do it wrong anybody does).
A simple test of usability/simplicity is to model a tree leaf. I'm not talking about a regular heart shaped smooth one. Made it with all its details, with organic deformation, like torsion, with assimetry irregularities and its sap nervures.
