I’d like to compute the outward normal vector field on a 2D smooth surface (mesh will triangular cells of topologic dimension 2) embedded in 3D.
I guess I could do it with numpy , the array of the vertices and the local-to-global index mapping (assuming coherent orientation amongst cells)… But I was wandering if there were a more “cleaver”, ''compact", “FEniCS-tics” way of doing such a thing ?
Maybe I did not get it right but the FacetNormal class computes normals on boundaries, right. As I am considering closed surfaces I don’t have boundaries (cf caption).
Are you suggesting to generate a 3D mesh of the whole volume defined by the closed surface and then compute FacetNormal on it ?
If so, I tried such a thing (adding a central point to the spherical mesh and defining tetrahedrons) but it seemed to take ages…