Patch and Nurbs Modeling

3- Patch Modeling:

A patch is an area of a patch object, defined by three or four surrounding edges and vertices. Controls described in this topic let you manipulate a patch object at the patch level. As well as moving and rotating patches, you can create a separate element by holding down the SHIFT key during a move operation. This creates a separate element of the selected patches

4-NURBS Modeling:

NURBS (Non-Uniform Rational B-Splines) are a technique for interactively modeling 3D curves and surfaces