CGAL 5.5 released

Changelog

3D Alpha Wrapping (new package)

• This component takes a 3D triangle mesh, soup, or point set as input, and generates a valid (watertight, intersection-free, and combinatorially 2-manifold) surface triangle mesh that contains the input. The algorithm proceeds by shrink-wrapping and refining a 3D Delaunay triangulation, starting from a loose bounding box of the input. Two user-defined parameters, alpha and offset, offer control over the maximum size of cavities where the shrink-wrapping process can enter, and the tightness of the final surface mesh to the input, respectively. Once combined, these parameters provide a means to trade fidelity to the input for complexity of the output.

  See also the announcement page.

2D Straight Skeleton and Polygon Offsetting (breaking change)

• Fix the output of the function CGAL::create_exterior_skeleton_and_offset_polygons_with_holes_2() to not take into account the offset of the outer frame.
• Fix the computation of the exterior offset of a polygon with holes that was not computing the offset of the holes

3D Convex Hulls

• Added an overload of the function CGAL::convex_hull_3(), which writes the result in an indexed triangle set.

2D Polygons

• Add vertex, edge, and hole ranges.
• The concept GeneralPolygonWithHoles_2 now requires the nested type Polygon_2 instead of General_polygon_2.

2D Regularized Boolean Set-Operations

• The concept GeneralPolygonSetTraits_2 now requires the nested type Construct_polygon_with_holes_2 instead of Construct_general_polygon_with_holes_2.

Combinatorial Maps

• Removed old code deprecated in CGAL 4.9 and 4.10 (global functions, and information associated with darts).

2D Arrangements

• Fixed the intersect_2, compare_y_at_x_right, and compare_y_at_x_left function objects of the traits class template Arr_geodesic_arc_on_sphere_traits_2 that handles geodesic arcs on sphere and applied a small syntactical fix to the tracing traits.

Tetrahedral Mesh Generation

• Added the function remove_isolated_vertices() as a post-processing step for the tetrahedral mesh generation.

Polygon Mesh Processing

• Added the function CGAL::Polygon_mesh_processing::orient_triangle_soup_with_reference_triangle_soup(), which enables re-orienting the faces of a triangle soup based on the orientation of the nearest face in a reference triangle soup.
• Added the function CGAL::Polygon_mesh_processing::compatible_orientations(), which enables to retrieve the (in)compatibility of orientations of faces from different connected components.
• Added the function CGAL::Polygon_mesh_processing::tangential_relaxation(), which applies an area-based tangential mesh smoothing to the vertices of a surface triangle mesh.
• Added the named parameter visitor to the function triangulate_hole(), which enables to track progress with callbacks.
• Added more functions in the visitor of the corefinement based methods to track progress.

Surface Mesh Simplification

• Introduced four variations of the Garland-Heckbert simplification algorithm based on the probabilistic approach of Trettner and Kobbelt (Fast and Robust QEF Minimization using Probabilistic Quadrics): GarlandHeckbert_plane_policies, GarlandHeckbert_probabilistic_plane_policies, GarlandHeckbert_triangle_policies, and GarlandHeckbert_probabilistic_triangle_policies.
• The class GarlandHeckbert_policies has been deprecated, GarlandHeckbert_plane_policies replaces it.

Point Set Processing

• A new optional named parameter, min_points_per_cell has been added to grid_simplify_point_set(). By adding a minimal number of points in a cell such that a point is retained, one can also filter out low density areas and outliers: in the case of densely sampled point clouds, this yields better results than using grid simplification and then outlier removal, while being very vast. The default value is 1 to keep the previous behavior as default.

dD Spatial Searching

• Added the member function write_graphviz() to the class Kd_tree that writes the tree in a stream in the Graphviz format.

CGAL and the Boost Graph Library (BGL)

• Added the function invert_selection() in the class Face_filtered_graph, which toggles the selected status of a graph: selected faces are deselected, and unselected faces are selected.