Use an Edge Map to control a Boundary Similarity nonlocal coupling mapping in 3D. Right-click the Boundary Similarity node to add a Edge Map subnode ().

To select a single Source edge and a single Destination edge, click the Active button to toggle between turning ON and OFF selections. The destination edge is mapped to the source edge by the similarity mapping from destination to source.

Select a relative Direction of the source and destination edges — Automatic orientation (the default), Same orientation, or Opposite orientation. This specifies the relative direction of the source and boundary edges and specifies which one of the two possible similarity mappings between the source and destination edge to use.