Tangent surface sets collect surfaces that have at least one tangent edge with another surface in the tangent surface set. When the seed surface is a surface region, the tangent surface set collects surface regions.

When you select a seed surface, other surfaces that share artificial edges with the selected surface are treated as part of the seed surface. For example, when you select one half of a cylinder, the seed surface includes both halves of the cylinder.

By default, all surfaces that form the tangent chain are collected. In the Surface Sets dialog box, you can only select the neighbors of the seed surface. As with all surface sets, you can exclude surfaces.