CGAL 5.6  3D Simplicial Mesh Data Structures

#include <CGAL/Simplicial_mesh_cell_base_3.h>
The class Simplicial_mesh_cell_base_3
is a model of the concept SimplicialMeshCellBase_3
.
It is designed to serve as cell base class for.3D simplicial mesh data structures. It stores and gives access to data about the complex the cell belongs to, such as the subdomain it belongs to or surface it takes part to.
Subdomain_index  Type of indices for subdomains of the discretized geometric domain. Must be a model of CopyConstructible , Assignable , DefaultConstructible and EqualityComparable . The default constructed value must match the label of the exterior of the domain (which contains at least the unbounded component). It must match the Subdomain_index of the model of the MeshDomain_3 concept when used for mesh generation. 
Surface_patch_index  Type of indices for surface patches (boundaries and interfaces) of the discretized geometric domain. Must be a model of CopyConstructible , Assignable , DefaultConstructible and EqualityComparable . The default constructed value must be the index value assigned to a non surface facet. It must match the Surface_patch_index of the model of the MeshDomain_3 concept when used for mesh generation. 
CGAL::Mesh_complex_3_in_triangulation_3<Tr,CornerIndex,CurveIndex>
CGAL::Mesh_cell_base_3
MeshDomain_3
MeshDomainWithFeatures_3