Surface normals for discrete surfaces
I am trying to understand how the normal direction for discrete surfaces is determined. I recreated 2d plane FEM meshes from Abaqus in gmsh, and then used the createGeometry() function to remesh them. I checked the elements in the GUI, and prior to the remeshing, the normals of the triangle elements have the direction i expected (in this case, all normals pointing upwards). However, after creating the geometry and remeshing, i get a mesh with "flipped" normals (all downwards).
I can "hack" around this by checking the normal vectors and setting a reverse meshing constraint, however i would like to understand how the orientation is determined in the first place.
Kind regards
Tim