fem.tet_faces_from_nodes

fem.tet_faces_from_nodes(mesh, nodes)

Boundary triangles all three of whose corners belong to nodes.

The tet analog of :func:faces_from_nodes: the bridge from node selections to area-integrated boundary conditions. Returns the raw (M, 3) corner triples (not a :class:FaceGroup) because the tet solver path targets faces by connectivity, not by geometry.