Iterate over all facets on mesh surface to obtain average values for each facet

Hi @CoE2845,

I think the FacetNormals are averaged over all facets that each node is part of. So only for nodes that are not on the boundary of the facet, the normals are the facet normals. If you increase the number of cells of your mesh, more and more of your arrows should truly be normal to the each facet, and only normals on edges and at vertices are not perpendicular to the box.

Maybe you can adapt some of the code from How to get average facet normals for each node? to fit your needs.

Note that the normal vector of a facet is constant over the entire surface of the facet.