Meshing Backends

Meshing Backends#

cad_to_dagmc supports two meshing backends for creating surface meshes.

Available Backends#

Backend

Description

Best For

GMSH

Full-featured meshing library

Complex models, volume meshes

CadQuery

Built-in CadQuery tessellation

Simple models, flat surfaces

Quick Comparison#

Feature

GMSH Backend

CadQuery Backend

Surface mesh (h5m)

Yes

Yes

Volume mesh (vtk)

Yes

No

Mesh size control

Full (min/max/per-volume)

Limited (tolerance only)

Mesh algorithms

10 algorithms

1 (built-in)

Parallel meshing

Yes

Partial

Dependencies

Requires GMSH

Built into CadQuery

Flat surface efficiency

Standard

Better (fewer triangles)

Choosing a Backend#

Use GMSH backend (default) when:

  • You need volume meshes for unstructured mesh tallies

  • You need precise control over mesh density

  • You want per-volume mesh sizing with set_size

  • You need parallel meshing for large models

  • You need specific mesh algorithms

Use CadQuery backend when:

  • You only need surface meshes

  • You want simpler configuration

  • Your geometry has many flat surfaces (fewer triangles)

  • You want to minimize dependencies

  • Your geometry is straightforward

Basic Usage#

import cadquery as cq
from cad_to_dagmc import CadToDagmc

assembly = cq.Assembly()
assembly.add(cq.Workplane("XY").sphere(10))

model = CadToDagmc()
model.add_cadquery_object(assembly, material_tags=["mat1"])

# GMSH backend (default)
model.export_dagmc_h5m_file(
    filename="dagmc_gmsh.h5m",
    meshing_backend="gmsh",
    min_mesh_size=0.5,
    max_mesh_size=10.0,
)

# CadQuery backend
model.export_dagmc_h5m_file(
    filename="dagmc_cq.h5m",
    meshing_backend="cadquery",
    tolerance=0.1,
    angular_tolerance=0.1,
)

Mesh Sizing Overview#

For detailed per-volume mesh sizing, see Mesh Sizing.

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