MeshHexer

A geometry grab-bag library.

Dependencies

To build MeshHexer you need:

• A C++17 compatible C++ compiler
• CMake version 3.28.3 or newer
• CGAL version 6.0.1 or newer
• Boost version 1.81 or newer
• PMPLibrary version 3.0.0 or newer

CGAL, Boost, and PMP will be downloaded and built automatically if they are not found by CMake.

Building

Assuming you cloned this repo to ~/meshhexer you can build the library via:

mkdir build
cd build
cmake ~/meshhexer
cmake --build . --target MeshHexer

Additionally run

cmake --build . --target meshhexer-cli

to build the corresponding command-line application. Or just run cmake --build ..

The following options are supported by the build system (defaults):

• MESHHEXER_ALLOW_EXTERNAL_DOWNLOAD: Enable automatic download of missing thirdparty libraries (ON)
• MESHHEXER_BUILD_APPLICATIONS: Enable building of applications (ON)
• MESHHEXER_DOCUMENTATION: Enable docs target (ON)
• MESHHEXER_DOCUMENTATION_INTERNAL: Add internal headers to documentation (OFF)
• MESHHEXER_HAVE_OMP: Enable OMP support (ON)
• MESHHEXER_INSTALL: Enable installation support (ON)
• MESHHEXER_PREFER_EXTERNAL_TPL: Prefer installed thirdparty libraries over downloading missing libraries (ON)
• MESHHEXER_SHARED_LIB: Build as a shared library (OFF)
• MESHHEXER_TESTING: Enable unit tests (ON)
• MESHHEXER_TPL_CACHE_DIRECTORY: Set cache directory for downloaded thirdparty libraries (None)

Installing

To install the library (and its dependencies, if they were built during the configure step) run

cmake --install . --prefix=path/to/install/dir

MeshHexer will be installed as a CMake package and can be found via find_package(MeshHexer) if the install directory is seen by CMake.

Documentation

MeshHexer is documented using Doxygen. To build the documentation run

cmake --build . --target doc

in a configured build directory.

By default only documentation for the public API of MeshHexer is build. You can build the documentation for internal code by settings the MESHHEXER_DOCUMENTATION_INTERNAL CMake variable to ON.

Tests

MeshHexer has a unit tests. To run the tests either build the whole project using

cmake --build .

or just the tests using

cmake --build . --target tests

Then run ctest to run the test suite.

Using MeshHexer

MeshHexer installs itself as a proper CMake package. After installation it can be found via a find_package(MeshHexer) call, if it has been installed to the usual system directories or some path in the CMAKE_PREFIX_PATH. After the find_package call you can link against the MeshHexer::MeshHexer CMake target.

If you have included MeshHexer as part of your build tree, for example by vendoring the library or via CMake's FetchContent mechanism, the MeshHexer::MeshHexer target will be available as well.

Build the documentation or see src/meshhexer.hpp for documentation on the public API.

meshhexer-cli

meshhexer-cli is a command-line application that gives access to MeshHexers's features without having to integrate the library into your own application.

Call as

meshhexer-cli [-h|--help] [<global args>] <command> <mesh> [<args>]

Running meshhexer-cli --help gives more detailed information.

The possible commands are

• fbm-mesh: Produce a non-fitted base mesh for a mesh-hierarchy suitable for a multigrid solver.
• min-gap: Heuristically try to find the smallest "real" gap between opposite faces of a surface mesh. Tries to discard gaps caused by local geometry, such as in that sharp edges of the mesh, and gaps caused by badly meshes surfaces.
• report: Generate a report about the given mesh. Includes topological information like whether the mesh is closed and the default orientation of surface normals, as well as defects like degenerate triangles.
• warnings: Generates a list of warnings about bad triangles of the mesh. Currently checks for self-intersecting triangles, degenerate triangles, and highly anisotropic triangles. Pass --summarize to get a summary of warnings, instead of printing each warning individually.