Between a C2 Continuous round or a D1 x D2 C2 round and another round, you can add the following transition types:

To achieve full curvature continuity between the transition and the rounds when you apply a Patch transition, the rounds must all be C2 Continuous or D1 x D2 C2. If a neighboring round surface is of another cross section type, the round surface and the patch surface are tangent to each other. The same is true when you select an Optional Surface to include in the transition.

An Intersect at Surface - side 1 or Intersect at Surface - side 2 transition is curvature continuous to the neighboring surfaces on every side, except at the edge where the rounds intersect.