All of these primitives are designed so that they are easy to manipulate and redimension. For instance, the cylinder and similar primitives are designed with only 4 lathe sections in order to align the sections along the axes and thus ease the dimensioning along those axes. With 8 lathe sections, some of the sections would lie on a 45° plane and it would be necessary to first turn the whole model 45° in order to redimension it precisely.

Click here to download a zip file containing all primitives.