The tool extracts either lines in case of a 2D bulk mesh as input or quads/triangles in case of a 3D bulk mesh as input. The input mesh can be given either in the VTU or MSH format. Since the algorithm uses the element surface normals a correct node ordering of the element nodes is required.
ExtractBoundary -i [<file name of input mesh>] [-o <file name of output mesh>]
New data arrays containing the original IDs for nodes, elements, and faces from the source mesh are added to the extracted surface mesh. These data arrays are required for specifying source terms or setting boundary conditions during a simulation run of OpenGeoSys.
ExtractBoundary -i square_1x1_quad.vtu -o square_1x1_quad_border.vtu
ExtractBoundary -i square_1x1_tri.vtu -o square_1x1_tri_border.vtu