API proposal for 3D mesh smoothing

Documentation/doc/Documentation/packages.txt

@@ -101,6 +101,7 @@
 \package_listing{Tetrahedral_remeshing}
 \package_listing{Periodic_3_mesh_3}
 \package_listing{Alpha_wrap_3}
+\package_listing{Mesh_smoothing_3}
 
 \cgalPackageSection{PartReconstruction,Shape Reconstruction}
 

Documentation/doc/biblio/cgal_manual.bib

@@ -3537,6 +3537,14 @@ @article{cgal:mamou2016volumetric
   publisher={AK Peters}
 }
 
+@unpublished{cgal:pcl-vvfaf-26,
+  author = {Francois Protais and Gianmarco Cherchi and Marco Livesu},
+  title = {Versatile Volume Fitting with Automatic Feature Preservation},
+  year = {2026},
+  note = {Working paper},
+  url = {https://inria.hal.science/hal-05574616}
+}
+
 % ----------------------------------------------------------------------------
 % END OF BIBFILE
 % ----------------------------------------------------------------------------

Documentation/doc/scripts/generate_how_to_cite.py

@@ -237,6 +237,7 @@ def protect_accentuated_letters(authors):
         .replace("%", "")
         .replace("đ", r"{\-d}")
         .replace("ï", r"{\"i}")
+        .replace("ç", r"{\,c}")
     )
     try:
         res.encode("ascii")

Installation/include/CGAL/license/Mesh_smoothing_3.h

@@ -0,0 +1,54 @@
+// Copyright (c) 2016  GeometryFactory SARL (France).
+// All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org)
+//
+// $URL$
+// $Id$
+// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
+//
+// Author(s) : Andreas Fabri
+//
+// Warning: this file is generated, see include/CGAL/license/README.md
+
+#ifndef CGAL_LICENSE_MESH_SMOOTHING_3_H
+#define CGAL_LICENSE_MESH_SMOOTHING_3_H
+
+#include <CGAL/config.h>
+#include <CGAL/license.h>
+
+#ifdef CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE
+
+#  if CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE < CGAL_RELEASE_DATE
+
+#    if defined(CGAL_LICENSE_WARNING)
+
+       CGAL_pragma_warning("Your commercial license for CGAL does not cover "
+                           "this release of the 3D Mesh Smoothing package.")
+#    endif
+
+#    ifdef CGAL_LICENSE_ERROR
+#      error "Your commercial license for CGAL does not cover this release \
+              of the 3D Mesh Smoothing package. \
+              You get this error, as you defined CGAL_LICENSE_ERROR."
+#    endif // CGAL_LICENSE_ERROR
+
+#  endif // CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE < CGAL_RELEASE_DATE
+
+#else // no CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE
+
+#  if defined(CGAL_LICENSE_WARNING)
+     CGAL_pragma_warning("\nThe macro CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE is not defined."
+                          "\nYou use the CGAL 3D Mesh Smoothing package under "
+                          "the terms of the GPLv3+.")
+#  endif // CGAL_LICENSE_WARNING
+
+#  ifdef CGAL_LICENSE_ERROR
+#    error "The macro CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE is not defined.\
+            You use the CGAL 3D Mesh Smoothing package under the terms of \
+            the GPLv3+. You get this error, as you defined CGAL_LICENSE_ERROR."
+#  endif // CGAL_LICENSE_ERROR
+
+#endif // no CGAL_MESH_SMOOTHING_3_COMMERCIAL_LICENSE
+
+#endif // CGAL_LICENSE_MESH_SMOOTHING_3_H

Installation/include/CGAL/license/gpl_package_list.txt

@@ -35,6 +35,7 @@ Kinetic_surface_reconstruction Kinetic Surface Reconstruction
 Matrix_search Monotone and Sorted Matrix Search
 Mesh_2 2D Conforming Triangulations and Meshes
 Mesh_3 3D Mesh Generation
+Mesh_smoothing_3 3D Mesh Smoothing
 Minkowski_sum_2 2D Minkowski Sums
 Minkowski_sum_3 3D Minkowski Sum of Polyhedra
 Nef_2 2D Boolean Operations on Nef Polygons

Mesh_smoothing_3/doc/Mesh_smoothing_3/Concepts/ConstructTangentSpace.h

@@ -0,0 +1,80 @@
+/*!
+\ingroup pkgMeshSmoothing3Concepts
+\cgalConcept
+
+The concept `ConstructTangentSpace` describes projection of mesh facets on target surfaces and
+mesh edge on target feature curves.
+
+\cgalHasModelsBegin
+\cgalHasModels{CGAL::Mesh_smoothing_3::C3t3_mesh_projector}
+\cgalHasModels{CGAL::Mesh_smoothing_3::C3t3_no_projection}
+\cgalHasModelsEnd
+
+\sa `CGAL::boundary_aware_mesh_smoothing`
+
+*/
+class ConstructTangentSpace {
+public:
+
+/// \name Types
+/// @{
+
+/*!
+Model of `MeshComplex_3InTriangulation_3`
+*/
+using C3t3 = unspecified_type;
+
+/*!
+Geom_traits
+*/
+using Geom_traits = typename C3t3::Triangulation::Geom_traits;
+
+
+/*!
+Point type.
+*/
+using Point_3 = Geom_traits::Point_3;
+
+
+/*!
+Face associated with a patch
+*/
+using Patch_face = std::pair<C3t3::Surface_patch_index, C3t3::Facet>;
+
+/*!
+Edge associated with a curve
+*/
+using Curve_edge = std::pair<C3t3::Curve_index, C3t3::Edge>;
+
+/*!
+Model of `TangentSpace`
+*/
+using Tangent_space = unspecified_type;
+
+
+/// @}
+
+
+/// \name Operations
+/// The following functions are used to project entities
+/// @{
+
+/*!
+returns a plane tangent to the patch to which its facet should align too.
+The list of Point_3 contains its current vertices location.
+*/
+Tangent_space patch_face_projection_plane(Patch_face patch_face, std::vector<Point_3> face_points) const;
+
+
+/*!
+returns a line tangent to the curve to which its edge should align too.
+The array contains the two current locations of its vertices.
+*/
+Tangent_space curve_edge_projection_line(Curve_edge curve_edge, std::array<Point_3,2> edge_points) const;
+
+
+/// @}
+
+
+
+}; /* end ConstructTangentSpace */

Mesh_smoothing_3/doc/Mesh_smoothing_3/Concepts/MeshDataStructure.h

@@ -0,0 +1,80 @@
+/*!
+\ingroup pkgMeshSmoothing3Concepts
+\cgalConcept
+
+The concept `MeshDataStructure` describes the way the tetrahedral mesh will be accessed and modified.
+
+\sa `CGAL::Mesh_smoothing_3::Mesh_smoother`
+
+*/
+class MeshDataStructure {
+public:
+
+/// \name Types
+/// @{
+
+/*!
+Descriptor used to access a cell (tetrahedron) information
+*/
+using Cell_descriptor = unspecified_type;
+
+
+/*!
+Descriptor used to access a vertex information
+*/
+using Vertex_descriptor = unspecified_type;
+
+
+/*!
+Point type.
+*/
+using Point_3 = unspecified_type;
+
+/// @}
+
+/// \name Operations
+/// The following functions are used to access and modify the mesh data:
+/// @{
+
+/*!
+std::size_t is optional but will avoid warnings.
+*/
+std::size_t nb_cells() const;
+
+/*!
+
+*/
+std::size_t nb_vertices() const;
+
+/*!
+Access the coordinates of a vertex.
+*/
+Point_3 vertex_coordinates(Vertex_descriptor vertex) const;
+
+/*!
+Change the coordinates of a vertex.
+*/
+void set_vertex_coordinates(Vertex_descriptor vertex, Point_3 coord);
+
+/*!
+Provide an iterable range over the Cell_descriptors of the mesh
+*/
+unspecified_type cell_range() const;
+
+/*!
+Access the 4 vertices of a cell.
+Returns container behaving like std::array<Vertex_descriptor, 4>
+*/
+unspecified_type cell_vertices(Cell_descriptor cell) const;
+
+/*!
+Optimal shape of the given cell.
+Returns container behaving like std::array<Point_3, 4>
+*/
+unspecified_type cell_reference_shape(Cell_descriptor cell) const;
+
+/// @}
+
+
+
+}; /* end MeshDataStructure */

Mesh_smoothing_3/doc/Mesh_smoothing_3/Concepts/PolylinesDataStructure.h

@@ -0,0 +1,63 @@
+/*!
+\ingroup pkgMeshSmoothing3Concepts
+\cgalConcept
+
+The concept `PolylinesDataStructure` describes the way the curves on the mesh will be accessed.
+
+\sa `CGAL::Mesh_smoothing_3::Mesh_smoother`
+\sa `MeshDataStructure`
+\sa `SurfaceDataStructure`
+
+*/
+class PolylinesDataStructure {
+public:
+
+/// \name Types
+/// @{
+
+/*!
+Descriptor used to access a edge information
+*/
+using Edge_descriptor = unspecified_type;
+
+/*!
+Index associated with an edge to identify the curve it belongs to. This is used to query the curve information from the user.
+*/
+using Curve_index = unspecified_type;
+
+/*!
+Descriptor used to access a vertex information. Must be compatible with the one used in MeshDataStructure.
+*/
+using Vertex_descriptor = unspecified_type;
+
+
+/// @}
+
+/// \name Operations
+/// The following functions are used to access surface data:
+/// @{
+
+/*!
+std::size_t is optional but will avoid warnings.
+*/
+std::size_t nb_edges() const;
+
+/*!
+Provides an iterable range over the Edge_descriptor of the mesh
+*/
+unspecified_type edge_range() const;
+
+/*!
+Returns an identifier (curve id, segment id, ...) related to an edge.
+*/
+Curve_index curve_id(Edge_descriptor edge) const;
+
+/*!
+Return the ith vertex of an edge (max 2).
+*/
+Vertex_descriptor edge_vertex(Edge_descriptor edge, unsigned i) const;
+
+/// @}
+
+
+}; /* end PolylinesDataStructure */

Mesh_smoothing_3/doc/Mesh_smoothing_3/Concepts/SurfaceDataStructure.h

@@ -0,0 +1,68 @@
+/*!
+\ingroup pkgMeshSmoothing3Concepts
+\cgalConcept
+
+The concept `SurfaceDataStructure` describes the way the surface mesh will be accessed.
+
+\sa `CGAL::Mesh_smoothing_3::Mesh_smoother`
+\sa `MeshDataStructure`
+
+*/
+class SurfaceDataStructure {
+public:
+
+/// \name Types
+/// @{
+
+/*!
+Descriptor used to access face information
+*/
+using Face_descriptor = unspecified_type;
+
+
+/*!
+Vector type.
+*/
+using Normal_3 = unspecified_type;
+
+/*!
+Index associated with a surface patch to identify the patch it belongs to. This is used to query the patch information from the user.
+*/
+using Surface_patch_index = unspecified_type;
+
+/// @}
+
+/// \name Operations
+/// The following functions are used to access surface data:
+/// @{
+
+/*!
+std::size_t is optional but will avoid warnings.
+*/
+std::size_t nb_faces() const;
+
+/*!
+Provides an iterable range over the Face_descriptor of the mesh
+*/
+unspecified_type face_range() const;
+
+/*!
+Returns the number of vertices of a face. std::size_t is optional but will avoid warnings.
+*/
+std::size_t nb_face_vertices(Face_descriptor face) const;
+
+/*!
+Returns an identifier (patch id, face id, ...) related to a face.
+*/
+Surface_patch_index patch_id(Face_descriptor face) const;
+
+/*!
+Provides an iterable range of Vertex_descriptor as defined in `MeshDataStructure` to iterate over the vertices of a face.
+*/
+unspecified_type face_vertices(Face_descriptor face) const;
+
+/// @}
+
+
+
+}; /* end SurfaceDataStructure */