Here explains how to define a contact surface for the Surface type contact (Smooth contact). In Figure 1, Body1 is rolling on the surface of Body2. In the definition of contact surface, Body1 can be regarded as one surface like Figure 2. In this case, the contact may not work correctly due to irregular patch shape. On the other hand, Body2 can be regarded as three surfaces like Figure 3. Since the patches have a regular pattern, this makes a noise minimized. (However, a little noise or discontinuity between contact surfaces can occur according to how to use Plane Tolerance Factor of three contact surfaces.) Figure 4 compares the result of one surface and three surfaces.
Figure 1 Contact force and Performance
Figure 2 one geometry
Figure 3 Divided force and Performance
Figure 4 Contact force and Performance