|barycenter||A center of gravity created between selected elements.|
|closed primitive||A closed surface on which a weight can be applied. It can be a sphere, a cylinder, a box, a pyramid or a torus.|
|open primitive||An open surface made of several faces. It can be rectangular, circular, triangular or ring-shaped.|
|subdivision||An algorithmic technique to generate smooth surfaces as a sequence of successively refined polyhedral meshes.|
|subdivision surface||A skin made of an elementary surface, that can be closed
The definition and the control of the shape is made using a mesh. This mesh is made of four-sided faces.