This is a unique set of CAD geometries with corresponding Constructive Solid Geometry (CSG). The intended use is for particle transport computational benchmarks. The collection of geometries provides particle transport codes an opportunity to verify particle transport is the same with both geometry types.
This benchmark is invaluable if you want to test that a particle transport code gets the same results in CSG and CAD geometry transport as it provides geometries that:
- cover all standard CSG surface types
- planes
- spheres
- cylinders
- tori
- cones
- general quadratics
- cover contacting and non-contacting geometries (to test imprint and merging)
- cover single and multibody geometries
- models are parametric so can easily be changed for parameter studies
I originally made this repository as there was no other comparison of CSG geometry with DAGMC geometry available and I wanted to verify the level of surface discretisation that was needed to provide accurate results.
The repository then grew into a way to test my DAGMC geometry making package cad-to-dagmc. Later on tests for cad-to-openmc which is another geometry making package were also added.
The table below lists all 56 models with details of each model. The combined collection covers a significant number of CAD meshing challenges, but feel free to make a pull request if there are more edge cases to cover.
| Model | Description | Materials | Meshing challenge |
|---|---|---|---|
|
Blanket module | 3 | Nested box shells with cylindrical coolant channel; multi-body imprint of curved and planar regions |
|
Simplified tokamak | 2 | Multi-body with nested curved shells and cylindrical penetration |
|
Nested tori | 4 | Double curvature with concentric toroidal shells requiring imprint and merge |
|
Cubic lattice | 2 | Eight-sphere 2×2×2 array in a cube; multi-body curved-to-planar imprinting at 8 locations |
|
Pebble bed cell | 4 | Multiple spheres inside a box; multi-body curved-to-planar imprinting with N pebbles |
|
Oktavian sphere | 2 | Nested spherical and cylindrical regions with complex boolean intersections |
|
Fuel pin cell | 3 | Concentric fuel/clad cylinders in a square cell; curved-to-planar imprinting at cylinder-box interface |
|
Concentric cylinders | 3 | Three nested cylindrical shells; multi-region imprint and merge on curved interfaces |
|
Pipe elbow | 1 | Hollow toroidal section; double curvature with thin annular wall and cut-plane end faces |
|
Divertor monoblock | 2 | Rectangular block with annular pipe bore; curved-to-planar boolean and thin-walled annulus |
|
Cylindrical intersection | 1 | Two perpendicular fused cylinders; curved-to-curved boolean with saddle-shaped intersection seam |
|
Sphere with multiple holes | 1 | Three orthogonal cylindrical booleans on a sphere; intersecting seam edges at hole crossings |
|
Elliptical torus | 1 | Non-uniform curvature from elliptical cross-section on a toroidal path |
|
Circular torus | 1 | Genus-1 topology with double curvature and saddle-point regions |
|
Toroidal sector | 1 | Partial torus arc with open cut faces; double curvature meeting flat end planes |
|
Overlapping spheres | 2 | Lens-shaped curved intersection seam between two partially overlapping spheres |
|
Hexagonal lattice cell | 2 | Cylindrical pin inside hexagonal prism; curved-to-planar imprint at 120-degree face junctions |
|
Capsule | 1 | Cylinder with hemispherical end caps; curved-to-curved tangent join at cap-barrel seam |
|
Ogive | 1 | Nose cone (spherical section); curved surface meeting a flat base plane at the perimeter |
|
Sphere with cylindrical hole | 1 | Curved-to-curved boolean intersection producing saddle-shaped seam edges |
|
Box with spherical cavity | 1 | Flat-to-curved boolean intersection; sharp curvature transition at cavity edge |
|
Eccentric nested cylinders | 2 | Non-concentric annular gap; varying thin-wall thickness around the circumference |
|
Hyperboloid | 1 | Negative Gaussian curvature surface; concave and convex directions simultaneously |
|
Thin-walled sphere | 1 | Curved thin shell; element quality in narrow gap between two concentric curved surfaces |
|
Thin-walled cylinder | 1 | Cylindrical thin shell; element quality in narrow annular gap between concentric surfaces |
|
Nested sphere | 2 | Concentric curved shells requiring conformal surface meshes at the shared interface |
|
Cylinder in box | 2 | Curved surface tangent to flat faces; cylindrical-to-planar imprinting along tangent lines |
|
Sphere in box | 2 | Curved surface enclosed in rectilinear body; pebble-in-moderator case |
|
Cross junction | 2 | Four-way body contact; non-coincident face imprinting at 4 re-entrant corners |
|
T-junction | 2 | Right-angle body contact; non-coincident face imprinting at a partial shared surface |
|
Paraboloid | 1 | Curvature varying from tight at the vertex to nearly flat far from the axis |
|
Ellipsoid | 1 | Non-uniform curvature with poles where mesh elements tend to collapse |
|
Three touching cuboids | 3 | Multi-body imprinting at T-shaped shared faces; triple-edge junction |
|
Nested cylinders | 2 | Concentric cylindrical shells; conformal meshing at shared curved interfaces |
|
Annular sector | 1 | Wedge slice of a cylindrical shell; curved surfaces meeting angled cut planes |
|
Stepped cylinder | 1 | Abrupt radius change at step; mesh grading at cylindrical-to-planar transition |
|
Cone | 1 | Degenerate apex where surface converges to a point; element collapse at tip |
|
Pyramid | 1 | Four flat faces converging to a degenerate apex point; element collapse at tip on planar faces |
|
Two tetrahedrons in contact | 2 | Shared triangular face with acute dihedral angles at all edges |
|
Two touching cuboids | 2 | Shared planar face imprinting between two bodies |
|
Elliptic cylinder | 1 | Non-uniform curvature around the cross-section; tight curvature at minor-axis ends |
|
Hemisphere | 1 | Curved-to-flat transition at the cut plane; sharp edge where sphere meets plane |
|
Sphere | 1 | Uniform curvature with poles; baseline for faceting error on curved surfaces |
|
Pipe | 1 | Hollow cylindrical wall; thin annular cross-section with inner void |
|
Truncated cone | 1 | Linearly varying radius; mesh grading from wide base to narrow top |
|
Wedge | 1 | Acute dihedral angle (~17 degrees); tet quality degrades at sharp edges |
|
L-shaped solid | 1 | Non-convex body with a sharp 90-degree re-entrant corner |
|
Hexagonal prism | 1 | Non-90-degree planar edge angles; 120-degree junctions between flat faces |
|
Chamfered box | 1 | Angled planar chamfer faces at non-90-degree edge intersections |
|
Cylinder | 1 | Single curvature surface; baseline for cylindrical faceting accuracy |
|
Cladded plate | 3 | Three-layer planar sandwich; multi-body conformal meshing at shared flat interfaces |
|
Thin gap | 2 | Two cuboids separated by narrow void gap; thin-slit meshing and streaming path fidelity |
|
Thin plate | 1 | High aspect ratio (20:1); thin-wall volume meshing with very few layers through thickness |
|
Tetrahedron | 1 | Acute edges and vertices; mesh quality at sharp corners of a simplex |
|
Cuboid | 1 | All-planar baseline; tests basic flat-face meshing and 90-degree edges |
First clone the repository:
git clone https://github.com/fusion-energy/model_benchmark_zoo.git
cd model_benchmark_zoopython -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
pip install .This uses an extra index for pre-built OpenMC wheels.
Requires a Conda/Mamba distribution:
mamba env create -f environment.yml
mamba activate model_benchmark_zoo
pip install .If the environment solve fails, you can try installing OpenMC from source instead.
Each model provides both a CSG definition and a CadQuery CAD assembly. Example scripts that compare CSG and DAGMC simulation results can be found in the examples folder.