OpenBimRL Engine Native

C++ shared library (OpenBIMRL_Native) wrapping IfcOpenShell and Open CASCADE for IFC geometry. Callable entry points are exported through the C ABI (include/openbimrl_c_api.h): stable symbol names and a plain calling convention so foreign runtimes (e.g. JNA on the JVM) can dlopen the library and invoke functions without C++ name mangling.

Responsibilities

• IFC model loading and geometry iteration (world coordinates)
• Element filtering, bounding boxes, building bounds, 2D polygons
• OpenMP pathfinding over extracted segments
• Element frame extraction (getElementFrame) from placement / extrusion
• JSON serialization helpers for IFC entities

Layout

.
├── CMakeLists.txt
├── cmake/                  # OCCT compat helpers
├── include/
│   ├── openbimrl_c_api.h   # Public C ABI for JNA
│   └── openbimrl/          # C++ domain headers
│       ├── model/
│       ├── geometry/
│       ├── properties/
│       ├── pathfinding/
│       └── ffi/
├── src/
│   ├── model/              # IfcSession, GUID, queries
│   ├── geometry/           # iterators, bounds, polygon, frames
│   ├── properties/         # IFC property snapshot + JSON
│   ├── pathfinding/        # Pure edge-cost algorithms
│   └── ffi/                # C ABI adapters + RuleContext
└── test/
    ├── unit/               # No IFC fixtures
    └── integration/        # IFC fixtures + end-to-end

Dependencies

Dependency	Purpose
IfcOpenShell	IFC parsing and geometry kernel
Open CASCADE (OCCT)	B-rep / mesh operations
Eigen3	Linear algebra
GMP / MPFR	IfcOpenShell numeric support
OpenMP	Parallel pathfinding

Build

cmake -B build -S . -DCMAKE_BUILD_TYPE=Release
cmake --build build -j --target OpenBIMRL_Native

CMake options

Option	Default	Description
OPENBIMRL_USE_PREBUILT_IFCOPENSHELL	OFF	Use a preinstalled IfcOpenShell prefix
OPENBIMRL_IFCOPENSHELL_PREFIX	/opt/ifcopenshell	Prefix with include/ and lib/
OPENBIMRL_STATIC_IFCOPENSHELL	OFF	Link IfcParse/IfcGeom statically into OpenBIMRL_Native (FetchContent builds static libs; prebuilt needs .a)
OPENBIMRL_BUILD_NATIVE_TESTS	OFF	Build gtest executables
OPENBIMRL_ENABLE_ROCM_OFFLOAD	OFF	ROCm OpenMP GPU offloading
OPENBIMRL_ROCM_OFFLOAD_ARCH	(empty)	GPU arch, e.g. gfx1100

Example with preinstalled IfcOpenShell:

cmake -B build -S . \
  -DOPENBIMRL_USE_PREBUILT_IFCOPENSHELL=ON \
  -DOPENBIMRL_IFCOPENSHELL_PREFIX=/opt/ifcopenshell
cmake --build build -j --target OpenBIMRL_Native

When IfcOpenShell is not on the default system path:

export LD_LIBRARY_PATH="${OPENBIMRL_IFCOPENSHELL_PREFIX}/lib${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}"

Tests

cmake -B build -S . \
  -DOPENBIMRL_BUILD_NATIVE_TESTS=ON \
  -DOPENBIMRL_USE_PREBUILT_IFCOPENSHELL=ON \
  -DOPENBIMRL_IFCOPENSHELL_PREFIX=/opt/ifcopenshell
cmake --build build -j --target OpenBIMRL_Native_UnitTest OpenBIMRL_Native_Test
ctest --test-dir build --output-on-failure

Exported API (C ABI)

Graph functions are implemented in C++ but exposed through the C application binary interface in openbimrl_c_api.h. Domain logic lives under src/{model,geometry,properties,pathfinding}; src/ffi only marshals.

Current entry points:

• initIfc, init_function
• filterByElement, filterByGUID
• getBoundingBox, getElementFrame, calculatingBuildingBounds
• request_geometry_polygon, copy_geometry_polygon
• request_ifc_object_json_size, ifc_object_to_json
• calculate_path_edge_costs

To add a function: implement domain logic under src/, add a thin adapter in src/ffi/, declare it in openbimrl_c_api.h, and list the source in CMakeLists.txt.