Integrations

Important

These integrations show how EBGeometry is coupled to a third-party application code. They are not built as part of EBGeometry’s continuous integration: unlike everything under Overview, which is compiled and run on every pull request, a change to a third-party platform (or to EBGeometry itself) can break them without anyone noticing. All of them were last compiled and run in October 2026, on CPUs and on an NVIDIA GPU (CUDA), against AMReX’s development branch (26.09); they have not been run with HIP. Treat them as a starting point for your own integration.

Each integration mirrors one or more of the Overview and hands the object it builds to AMReX’s embedded-boundary grid generation as an implicit function, on a domain around the object’s box with cubic cells. The geometry lives in an EBGeometry Pool (see Memory model) that must outlive every evaluation, and the implicit function holds the object by value. Several read a mesh from the common-3d-test-models git submodule by default (see Obtaining EBGeometry).

Everything in EBGeometry is negative inside an object and positive outside it. AMReX reads negative values as fluid, so every implicit function here returns the negated value, and the fluid is around the object. The sign is flipped at the boundary between the two codes, never by complementing the EBGeometry object.

Folder	What it hands over	Mirrors
`Shapes`	One analytic shape, a torus (the least a coupling needs), or the classic CSG solid, compiled into a `Tape` or composed with the fused operations (`shape = torus`, `csg` or `fused`).	Shapes, Basic CSG, Fused CSG
`MeshSDF`	A surface mesh as a `TriMeshSDF`.	MeshSDF
`MeshCSG`	The dragon on a table, blended by a smooth union, in a `Tape`.	CSG with a mesh
`Materials`	The armadillo with a bored cylinder, in a `Tape`, and each cut cell labeled with its closest leaf (`closestPrimitive()`) and, on the mesh, its closest face (`getClosestFace()`).	Materials
`ManyObjects`	3,000 spheres in a cylinder joined by a `BVHSmoothUnion` (the fluid is between them), or a city of boxes in a `BVHUnion` (`scene = spheres` or `city`).	Packed spheres, ManyObjects

AMReX

The Integrations/AMReX/<something> folders couple EBGeometry to AMReX’s EB2 grid generation and write a plot file. AMReX must be installed separately, with AMREX_HOME pointing to it.

The implicit function derives from amrex::GPUable, so the same code runs on CPUs and, in a CUDA or HIP build of AMReX, on GPUs. In a GPU build the pool is frozen and mirrored to device memory in one piece (see GPU builds (CUDA and HIP)), and the implicit function holds two views of the object, one of each copy; each compilation pass uses its own. An analytic shape is a plain value and needs no copy. A SYCL build of AMReX is rejected at compile time, since EBGeometry has no SYCL memory resource yet.

A mesh’s fine features can cut a cell edge more than twice, which EB2 refuses unless it may cover such cells, so the integrations set eb2.cover_multiple_cuts = 1 unless the inputs say otherwise.

See the README in each folder for build and run instructions.