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?