surface1 ... surfaceN = component surfaces
u1, u2 ... 1 = transition values for the u parameter
A PolySurf splices two or more surface objects together end-to-end to create a single surface. The principal reason for wanting to do this is to reduce the total number of surface meshes required to represent your model. For example, in some forms of computational fluid dynamics (CFD) analysis it is desirable to minimize the number of surface patches, to avoid complications of matching meshes and establishing neighbor connections between adjacent patches.