You can create an extended surface round only on edges by specifying a radius larger than the adjacent surface of the edge. When you create an extended surface round, the system determines the surfaces to be extended or trimmed to close any gaps and attaches the round to the model. You can use closed loop edges or open loop edges to create an extended surface round.

You can create concave rounds on step-like geometry only in solid models. When you create a concave round you can specify whether you want to attach the round as a solid or as a surface. If you attach the round as a solid, the neighboring surfaces are extended. If you attach the round as a surface and cap the side and end surfaces, the system extends the neighboring surfaces, caps the end and side surfaces, and creates a new quilt.

If you attach concave rounds as a surface and do not cap the side and end surfaces, the round is created as a separate new quilt.

When you create a convex round and attach it as a solid or as a same quilt, the radius of the round is maintained and the adjacent geometry is trimmed. However, if you attach the convex round as a surface or as a new quilt, the radius of the round is maintained and a new quilt is created, but geometry is not removed, regardless of whether you cap the side and end surfaces.

When you convert a regular round to an extended surface round, all information about the round pieces in the set is discarded. Transitions are visible only in the Transition mode and not in the Set mode. Transition geometry accounts for the surface extensions. An extended surface round supports the following transition types: