There are many ways to create procedural surfaces from existing surfaces. These include blending, patching, and offsetting or creating network and planar surfaces.
When you create procedural surfaces, use SURFACEASSOCIATIVITY to work with the surfaces as a group. Just as you can modify the face of a solid and have the entire solid update, when you modify a group of surfaces that are associative, all of the surfaces update accordingly.
Create planar surfaces in the space between edge subobjects, splines and other 2D and 3D curves.
Create non-planar surfaces in the space between edge subobjects, splines and other 2D and 3D curves.
Create a parallel surface a specified distance from the original surface.