I’m currently trying to implement a project using the Hyperbolic_Delaunay_Triangulation_2 and the Constrained_Delaunay_Triangulation_2 demos from CGAL. In short, I took the Traits-class from the former demo and used it with a Constrained_Delaunay_Triangulation_2. The Traits-class is for hyperbolic geometry, and inherits from the Exact_predicates_exact_construction_kernel_with_sqrt. I added and overwrote the orientation properties, since this isn’t the case in the original Traits-class from the demo. The overwritten orientation functionality uses the already implemented Side_of_oriented_hyperbolic_segment_2. This way, I managed to be able to insert points in the constrained triangulation, and non-intersecting constraints, all without any problems. But now I tried to insert intersecting constraints in the triangulation and some (for me) strange problems occured.

When using CGAL to operate ‘Minkwoski_sum_2’ and produce ‘no-fit-polygons’, some polygons resulted with duplicate points. For example, taken from the terminal output (result of the ‘print_polygon_with_holes()’ function left in the usage examples):

Instead of Point_3 I want to use std::pair<Point_3, unsigned> to generate TIN. How to mix Surface_mesh, Projection_traits_xy_3, Triangulation_vertex_base_with_info_3 and Delaunay_triangulation_2

I need to save the surface of a specified volume subdomain in a complex 3 to stl. I am using facets_in_complex_3_to_triangle_mesh in order to extract the triangle mesh. I have seen this function has a named parameter face_patch_map that can be passed to it, however if I understand correctly this is to specify the id’s the patches will be getting, not including/excluding them from the output. write_STL does not seem to allow selecting which subdomain to export either. Is there a build in function to achieve what I am looking for or is the only option to extract the desired subdomain manually from the complex 3?

I need to create meshes using anisotropic metrics derived from level-sets and have been looking if CGAL is capable of doing something like this but so far found nothing on the topic. Is this within the capabilities of CGAL, and if so, is there somewhere I can find some documentation on it?

I have a .mesh containing a triangulation with edges to protects, i.e. it only has Vertices, Triangles and Edges (no Tetrahedra). From this file I need to extract the edges to create polylines to protect in a hybrid domain meshing. The issue I am encountering is that I am finding no way to read this file using CGAL functions. CGAL::IO::write_MEDIT() seems to require a .mesh file containing tetrahedra since when reading to a CGAL::Polyhedron_3 it fails to read the file and when using CGAL::Surface_mesh<Point_3>, which in ways seems a more logical choice, it fails compilation with error: no type named ‘Periodic_tag’ in ‘class CGAL::Surface_mesh.