CGAL is a software library that offers a number of reliable geometric data structures and algorithms. CGAL components operate in 2D and 3D, and sometime in arbitrary dimensions. Examples of components include convex hulls, convex decomposition, Delaunay triangulations, Voronoi diagrams, polygonal surface mesh data-structures, mesh generation, Boolean operations, envelope computations, intersection detection, surface reconstruction, and subdivision surfaces. CGAL is used in a variety of application domains such as CAD/CAM (computer aided design and modeling), GIS (geographic information systems), geophysics, image processing, molecular biology, robotics, motion planning, and graphics. CGAL is written in C++ and rigorously adheres to the generic-programming paradigm. CGAL became an Open Source project in 2003. Most of CGAL is under the GPL v3+ license, and some core parts are under the LGPL v3+. The semi-annual releases have currently about 10,000 downloads. CGAL is commercially supported by the spin-off company GeometryFactory.