CM2 MeshTools® SDK /release 5.6.0

• Lib names now end with _56 (Windows®), 5.6.0 with symlinks from 5.6 (Linux®, macOS®).
• New builds with gcc 15.1 and clang 20 on Linux (Fedora 42).
• CM2 SurfMesh T3 and CM2 SurfMesh Q4 Windows (Visual Studio 2017, 2019, 2022 only) builds upgraded to OpenCascade 7.9.
  Linux builds (clang 20 and gcc 15.1 on F42 only) upgraded to OpenCascade 7.8.
  Other builds (Visual Studio 2010/2015, Linux gcc 4.8/8.5/12/clang 14, macOS) remain based on OpenCascade 7.6.
• Visual Studio 2015 deprecated (will be no longer provided in future versions).

CM2 SurfMesh T3, CM2 SurfMesh Q4

• New data_type::vertex_H (resp. curve_H, surface_H) for user-defined mesh sizes (isotropic) on specific vertices (resp. curves, surfaces).
  The precedence order is:
  1. vertex_H (highest precedence).
  2. curve_H.
  3. surface_H.
  4. settings_type::target_h (lowest precedence).

  Note that the mesher may use reduced mesh sizes in all directions (when settings_type::chordal_control_type = 1 or 3) or in selected directions (when settings_type::chordal_control_type = 2 or 4) to honor the settings_type::max_chordal_error criterion.

CM2 HexaMesh Iso

• New settings_type::conformation_level (replacing settings_type::make_conformation_flag, see Breaking Changes below).
  The value for this setting can be:
  • 0 : Minimal conformation: nothing specific is done to force conformal joints in the mesh.
    Non-conformal joints (i.e. quad faces connected to two triangle faces) are possible everywhere in the mesh but many joints can be still be conformal (i.e. quad faces connected to quad faces, triangle faces connected to triangle faces).
    Equivalent to former settings_type::make_conformation_flag = false.
  • 1 : Partial conformation: conformal joints are enforced only near the hard quadrangles. Joints elsewhere inside the domain can still be non-conformal. This type of conformation is new in this release.
  • 2+: Full conformation: conformal joints are enforced everywhere in the mesh.
    Equivalent to former settings_type::make_conformation_flag = true. The default.
• New settings_type::hard_quads_enforcement_flag to force the recovery of hard quadrangles (as much as possible).
  If the recovery of all boundary (or any hard embedded) quadrangles isn’t a requirement for you and the split into pairs of triangles is acceptable, you can turn off this flag to save nodes, elements and get a better mesh (usually).
  Conversely, this flag set (true) together with settings_type::conformation_level >= 1 forces the recovery of all boundary quadrangles. The default.

Core MeshTools libs

• New meshtools::vizir_sols to output solutions (scalars, vectors, tensors, matrices) for VIZIR (the new name of MEDIT).
  Note that the meshtools::medit_output, meshtools::medit_vector and meshtools::medit_tensor are replaced with their equivalent vizir functions or deprecated (see Breaking Changes below).
• New meshtools2d::mesh_parallelepiped_Q4 and meshtools2d::mesh_parallelepiped_T3 to generate structured surface meshes on parallelepipeds with CM2_FACEQ4 or CM2_FACET3 elements.
• The meshtools2d::get_element_containing_point (no longer experimental) can now search for 3-D points in a surface mesh (not only for 2-D points in plane meshes).
  In addition, works now also on quadratic meshes (with caveats).
• New meshtools2d::get_elements_containing_points to search for a set of points (2-D or 3-D) in a plane or surface mesh (linear or quadratic).
• New meshtools3d::get_elements_containing_points to search for a set of points (3-D) in a solid mesh (tetrahedrons only, linear or quadratic).

COM wrapper

• Updated.

All meshers (except specialized tools)

• Significant speed-ups when using settings_type::target_metric and settings_type::max_gradation, especially with the anisotropic mesh generators (CM2 TetraMesh Aniso can show speed-ups of 300% on large meshes).
• Improvements in the shape qualities after the refine step (especially CM2 TetraMesh Aniso).
  This has several nice outcomes:
  • The mesh sizes (isotropic and anisotropic) are better honored.
  • It makes the optimization step easier and faster.
  • The final mesh can be significantly better.
• Additional scheme in the optimizers to remove long edges.

CM2 QuadMesh Iso, CM2 QuadMesh Aniso, CM2 SurfMesh Q4, CM2 SurfRemesh Q4

• Fortified all-quad mode: fewer CM2_DEGENERATED_ELEMENT errors.
• Somewhat faster optimization step (up to 15%) in large meshes.

CM2 SurfMesh T3, CM2 SurfMesh Q4

• Improvements in the quality of meshes.
• Better generation along curves with high gradients of tangents (see below about meshtools1d::mesh_curve_param).

CM2 TetraMesh Iso, CM2 TetraMesh Aniso

• Fewer Steiner nodes (again).
• Improvements in the quality of the generated meshes in some cases.

CM2 TetraMesh Aniso

• Speed-ups (about 20%) even when settings_type::target_metric and settings_type::max_gradation aren’t used.

CM2 HexaMesh Iso

• More structured meshes (all-hexes).
• More OMP-parallelization (average gain = 15% on a 8-SMT CPU).
• Speed-ups in single-thread (average gain = 5%).

Core MeshTools libs

• meshtools1d::mesh_curve_param: improvements in the size of edges when curves have high gradients of tangents.

All meshers (except specialized tools)

• The settings_type::max_gradation wasn’t always properly honored (the actual gradations could be excessive).
• The settings_type::load function failed on Linux and macOS.

CM2 SurfMesh T3, CM2 SurfMesh Q4

• The bug in meshtools1d::mesh_curve_param (see below) could caused non-optimal meshes.
• The bug in meshtools2d::mesh_surface_param (see below) could caused strange aligned refinements.
• Loop curves couldn’t be merged.

CM2 SurfMesh Q4

• In all-quad mode: failed meshing surfaces when their contour had degenerated curves (segments with the two vertices merged together).

CM2 SurfRemesh T3, CM2 SurfRemesh Q4

• Could fail or even crash when settings_type::refine_flag = false.

CM2 HexaMesh Iso

• Could crash with target_metric.

CM2 Intersect T3

• Spurious splits on regular (non-intersecting) edges sometimes.

Core MeshTools libs

• meshtools::node_detector: errors when the coordinates matrix has two rows but a greater leading dimension (for instance 3).
• meshtools::NASTRAN_input: elements aren’t read when the PID fields are void.
• meshtools1d::mesh_curve_param: bug in 3-d metric reduction.
• meshtools2d::mesh_surface_param: non-optimal background mesh generation.
• meshtools2d::mesh_disk_UR_T3, meshtools2d::mesh_disk_UR_Q4, meshtools2d::mesh_disk_T3, meshtools2d::mesh_disk_Q4: bugs with non-empty initial matrices (coordinates and/or connectivity).

CM2 TriaMesh Iso, CM2 TriaMesh Aniso, CM2 TetraMesh Iso, CM2 TetraMesh Aniso

• Setting 'bool no_clamped_edges_flag' replaced with 'unsigned no_edge_with_nodes_below'.
  With the former flag, users were able to forbid edges between any two hard nodes (any nodes of the boundaries or embedded hard nodes). The new setting allows for a greater freedom over the type of edges to forbid.
  Consider nodes ordered in the data_type::pos matrix such that the highest boundary node id (say Nb) is before (i.e. smaller) than any other embedded node ids. Then no_edge_with_nodes_below = Nb+1 forbids any edge between two boundary nodes but still allows edges between a boundary node and an embedded node or between two embedded nodes.
  Conversely, if nodes are ordered such that the last embedded node (say with id Ne) is before any boundary nodes, then no_edge_with_nodes_below = Ne+1 forbids any edge between two embedded nodes but still allows edges between a boundary node and an embedded node or between two boundary nodes.
  no_edge_with_nodes_below = 0 (the default) is equivalent to the former default setting no_clamped_edges_flag = false.
  no_edge_with_nodes_below = data.pos.cols() is equivalent to the former setting no_clamped_edges_flag = true.

CM2 SurfMesh T3, CM2 SurfMesh Q4

• Upgraded to OpenCascade 7.9.1 on Windows (except the Visual Studio 2010 and 2015 builds).
  Note: the OCCT 7.8 libs are binary compatible.
• Upgraded to OpenCascade 7.8.1 on Fedora 42. Other Linux and macOS builds remain based on OCCT 7.6.
• The output fields data_type::color, data_type::colorE, data_type::merged_vertices, data_type::merged_curves and data_type::failed now follow the CAD indexing scheme.
  As OOCT has a 1-base indexing scheme, all these fields are 1-shifted vs. the previous version.

CM2 SurfMesh T3, CM2 SurfMesh Q4 (source-code licenses only)

• New requested enum in the CAD interface cad_interface::INDEX_BASE to specify the indexing scheme (0 or 1).
• New requested function in the CAD interface 'int cad_interface::orientation (const edge_type& E);' to give the orientation (+1, -1 or 0) of an edge.
• New requested functions in the CAD interface 'bool is_Uclosed (const surface_type& S);' and 'bool is_Vclosed (const surface_type& S);'
  to help tell whether a surface is periodic or not, on top of 'bool is_periodic (const surface_type& S, double& U_period, double& V_period);'.
• New requested function in the CAD interface 'bool periodic_surfaces_supported();' to tell whether the kernel supports periodic surfaces or not.

CM2 HexaMesh Iso

• bool settings_type::make_conformation_flag is replaced with unsigned settings_type::conformation_level.
  The former make_conformation_flag = false is now equivalent to conformation_level = 0.
  The former make_conformation_flag = true is now equivalent to conformation_level = 2.
• The internal formula used to compute the shape-quality of an hexahedron has changed (now gives higher values for elongated elements).

Core MeshTools libs

• meshtools::shape_qualities, meshtools::min_quality: changed values for hexahedrons (the new values are usually higher).
• meshtools::medit_output, meshtools::medit_vector and meshtools::medit_tensor are replaced with their equivalent vizir functions (some are just deprecated for the moment).
• meshtools2d::get_element_containing_point (no longer experimental) has gained a new output parameter: the reference coordinates (2-D) of the point in the containing element.
• meshtools3d::get_element_containing_point (no longer experimental) has gained a new output parameter: the reference coordinates (3-D) of the point in the containing element (tetrahedrons only).