# get all nodes which lie on the plane \a plane_1
filter = smesh.GetFilter(SMESH.NODE, SMESH.FT_BelongToPlane, plane_1)
ids = mesh.GetIdsFromFilter(filter)
# get all nodes which lie on the plane \a plane_1
filter = smesh.GetFilter(SMESH.NODE, SMESH.FT_BelongToPlane, plane_1)
ids = mesh.GetIdsFromFilter(filter)