So, I think that I just have to pick only one cell, take its first and second vertices, take the cross product and see if is pointing outwards from the surface. Is this correct?
Yes, though it won't hurt to check for all cells. The glossary entry Sebastian pointed to doesn't currently include a link to the Triangulation::flip_all_direction_flags() function you may be interested in. Best W. _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
