EBGeometry is a header-only C++17 library for constructive solid geometry (CSG) with implicit functions. It can turn surface geometries into fast, queryable signed distance functions (SDFs), and manipulate them with CSG operations.
Main features:
- Turn surface meshes into SDFs, via a half-edge (DCEL) mesh representation or raw triangles.
- Fast SDF evaluation using bounding volume hierarchies (BVHs).
- Supports both pointer-based tree BVHs, and flattened SIMD-accelerated packed BVHs.
- A library of analytic signed distance functions and implicit functions (spheres, boxes, and more)
- Composable with transforms (translation, rotation, scaling, rounding, blending).
- BVH-accelerated constructive solid geometry (CSG): unions, intersections, differences, and smooth blends, of both meshes and analytic shapes.
- Readers for triangulated surface meshes in STL, PLY, OBJ, and VTK format.
- Drop-in precision-templated for flexible usage.
- No external dependencies -- drop
EBGeometry.hppinto any C++17 project and include it.
The EBGeometry documentation is updated on every pull request and is a live document that evolves together with the code. There are three types of documentation available:
- HTML -- The user guide: concepts, building, testing, and examples.
- PDF -- The same user guide, as a single PDF.
- Doxygen -- The generated API reference for every class and function.
Clone the repository, including the submodule that provides the example mesh files:
git clone --recurse-submodules https://github.com/rmrsk/EBGeometry.git
cd EBGeometryBuild and run the MeshSDF example, which reads a triangulated surface mesh and
evaluates it as a signed distance function:
cd Examples/MeshSDF
g++ -std=c++17 -O3 -march=native -I../.. main.cpp -o MeshSDF.ex
./MeshSDF.exThis loads armadillo.obj from the common-3d-test-models submodule by default; pass a path to
run it on a different STL/PLY/OBJ/VTK file instead. MeshSDF -- like every example
under Examples/ -- can also be built with CMake or GNU make, see
Examples/MeshSDF/README.md for the exact
commands, and the Examples page for the full
list of bundled examples.
Examples that couple EBGeometry to a third-party application code
(AMReX, Chombo) live under ThirdParty/ instead -- see its README
for an important caveat about how those are maintained.
The repository ships CMake presets
that build the unit-test suite and every example under Examples/ in one step, and run them
through ctest:
cmake --preset debug # configure: Debug, assertions on, tests + examples enabled
cmake --build --preset debug --parallel $(nproc)
ctest --preset debug # unit tests only (Catch2), sub-second
ctest --preset examples --parallel $(nproc) # every example under Examples/, several minutes in Debug modecmake --preset release-test builds the same thing optimised (no assertions, AVX), and
cmake --preset debug-san additionally enables AddressSanitizer and UndefinedBehaviorSanitizer.
See Contributing and testing for the full
preset table, how to run a single test file, and Scripts/run-all-checks.sh, which reproduces
everything the continuous integration pipeline checks in one local command.
If you encounter any issues when installing or using EBGeometry, you may obtain help through:
- GitHub issues -- bug reports and feature requests.
- GitHub discussions -- usage questions and everything else.
We welcome contributions to EBGeometry -- the best approach is either to reach out to us to see if we have time to implement a specific feature, or fork the repository and submit a pull request. See Contributing and testing in the user guide for how to build and run the test suite locally, what the continuous integration pipeline checks, and the code style/conventions expected of contributions.
As of 2026, we have begun to take advantage of expert-steered AI code development. A CLAUDE.md lives in this project, which can be used to steer Claude code. Code contributions written by an AI coding agent are thus welcome. All merged code, however, is always reviewed by a human before accepted.
