Subject: CGAL 5.3 Beta 1 Released, Computational Geometry Algorithms Library Content-Type: text/plain; charset="utf-8" Body: The CGAL Open Source Project is pleased to announce the release 5.3 Beta 1 of CGAL, the Computational Geometry Algorithms Library. CGAL version 5.3 Beta 1 is a public testing release. It should provide a solid ground to report bugs that need to be tackled before the release of the final version of CGAL 5.3 in July 2021. Besides fixes and general enhancement to existing packages, the following has changed since CGAL 5.2: Quadtrees, Octrees, and Orthtrees (new package) - This package implements a tree data structure in which each node encloses a hypercubic section of space and each non-leave node has hypercubic children whose edge lengths are half its edge length. Such a data structure is known as a quadtree in 2D, an octree in 3D, and is generalized as an “orthtree” in higher dimensions. https://www.cgal.org/2021/04/27/Orthtree/ https://doc.cgal.org/5.3/Manual/packages.html#PkgOrthtree Triangulations on the Sphere (new package) - This package enables the construction and manipulation of Delaunay triangulations on the 2-sphere. Triangulations are built incrementally and can be modified by insertion or removal of vertices. Point location querying and primitives to build the dual Voronoi diagram are provided. https://doc.cgal.org/5.3/Manual/packages.html#PkgTriangulationOnSphere2 File Input / Output - Point set, polygon soup, and polygon mesh file I/O functions have been harmonized and documented: - Point set I/O functions can be found in the packages Point_set_processing_3, and Point_set_3. - Polygon mesh I/O functions can be found in the package BGL. - Polygon soup I/O can be found in the package Stream_support. A comprehensive list of the supported file formats is available in the Stream_support package: https://doc.cgal.org/5.3/Stream_support/index.html#IOstreamSupportedFormats Inversely, the following page can be used to find out which CGAL data structures can be used given a specific file format. https://doc.cgal.org/5.3/Stream_support/IOStreamSupportedFileFormats.html Requirements - The CMake minimal version is now 3.14. - The GNU compiler g++ versions 6 and 7 are no longer tested. Only version 8.3 or later are supported 2D and 3D Linear Geometry Kernel - Added is_translation(), is_scaling(), is_reflection(), and is_rotation() to the classes Aff_transformation_2 and Aff_transformation_3, which enable determining if the transformations use a specialized representation internally. 2D Regularized Boolean Set-Operations - Added documentation for the free functions oriented_side(const Point_2& p, ....) that accept a point and a polygon. - Documentation has been improved across the whole package. Polygon Mesh Processing - Added the class CGAL::Polyhedral_envelope, providing a way to quickly check if a primitive (point, segment, or triangle) is within a polyhedral envelope around a set of triangles. It is based on the work of Bolun Wang, Teseo Schneider, Yixin Hu, Marco Attene, and Daniele Panozzo. “Exact and efficient polyhedral envelope containment check.” (ACM Trans. Graph., 39-4, July 2020). - Added more functions in the visitor of the corefinement based methods to track all edge creations. Surface Mesh Topology - Added the function CGAL::Surface_mesh_topology::Curves_on_surface_topology::is_homotopic_to_simple_cycle(), which can be used to determine whehter a closed path on a surface mesh can be continously transformed to a cycle without self intersection. Surface Mesh Simplification - Added a filtering mechanism so that costly tests get only applied to the next candidate for the edge collapse. - Added the class Polyhedral_envelope_filter, which enables to perform mesh simplification inside a polyhedral envelope of the input mesh. 2D Polyline Simplification - When polylines have common subsequences of vertices, these subsequences may now be simplifified simultaneously. dD Triangulations - Added the function insert_if_in_star() to the class CGAL::Regular_triangulation, which enables users to insert a point p in a regular triangulation on the condition that p appears post-insertion in the star of a user-specified, existing vertex. 2D and 3D Alpha Shapes - Breaking change: The following deprecated classes have been removed: Alpha_shape_euclidean_traits_2, Weighted_alpha_shape_euclidean_traits_2, Alpha_shape_euclidean_traits_3, and Weighted_alpha_shape_euclidean_traits_3. All CGAL kernel can be used directly as models of the concepts of the 2D and 3D Alpha Shape packages. Classification - Breaking change: the support for TensorFlow has been dropped; the classifier CGAL::TensorFlow::Neural_network_classifier has been removed. The CGAL project is a collaborative effort to develop a robust, easy-to-use, and efficient C++ software library of geometric data structures and algorithms, like - triangulations (2D constrained triangulations, Delaunay triangulations and periodic triangulations in 2D and 3D), - Voronoi diagrams (for 2D and 3D points, 2D additively weighted Voronoi diagrams, and segment Voronoi diagrams), - Boolean operations on polygons and polyhedra, - regularized Boolean operations on polygons with curved arcs - arrangements of curves, - mesh generation (2D, 3D and surface mesh generation, surface mesh subdivision and parametrization), - alpha shapes (in 2D and 3D), - convex hull algorithms (in 2D, 3D and dD), - operations on polygons (straight skeleton and offset polygon), - search structures (kd trees for nearest neighbor search, and range and segment trees), - interpolation (natural neighbor interpolation and placement of streamlines), - optimization algorithms (smallest enclosing sphere of points or spheres, smallest enclosing ellipsoid of points, principal component analysis). Some modules are distributed under the terms of the LGPL Open Source license (GNU Lesser General Public License v3 or later versions). Most modules are distributed under the terms of the GPL Open Source license (GNU General Public License v3 or later versions). If your intended usage does not meet the criteria of the aforementioned licenses, a commercial license can be purchased from GeometryFactory (http://www.geometryfactory.com/). For further information and for downloading the library and its documentation, please visit the CGAL web site: https://www.cgal.org/