Mesh Generation

Mesh Generation#

This tutorial assumes a live XCOMPUTE-CLIENT/XCOMPUTE-SERVER session with the interface set to the Geometry tab.

Nodal points specify where data is stored and transported. Efficient node placement is critical for resolving spatial physics. Default preferences can be customized in compute.cfg via Settings → Compute Server.

Start with surfaces imported from STL, OBJ, or MSH. The workflow is similar for tetrahedral and hexahedral meshes.

References & Spatial Domain#

Activate the desired system or select surfaces. The associated system(s) define the bounding domain.

  • Meshes are generated as children of the active system.

  • Watertight surfaces are required for reliable SDF generation. Self-intersecting/overlapping surfaces are tolerated, but inverted/missing faces cause downstream errors.

  • To separate surface manifolds for boundary conditions: right-click → tools → segment, or enable auto-segment during import. Regions will colorize and map to generated meshes.

Note:

  • Single surface: proximity studies

  • Multiple surfaces: cross-surface studies

  • Domains adjustable in meshing dialog

Tetrahedral Mesh#

Right-click → New → Tet Mesh to open the dialog.

Solid vs Fluid#

Presets adjust sizing parameters for structural FEA vs CFD requirements.

  • Interior (default for solid): negative boundary normal

  • Exterior (default for fluid): positive boundary normal

Quantity vs Quality#

Node Count#

Target nodes for the mesh. Typical engineering meshes: 10k–10M nodes. Start with 30k–100k.

  • Tet meshes: ~6 elements per node

  • Hex meshes: ~1 element per node

  • Memory: ~2–3 kB per node

Shape Resolution#

Structured background grid for SDF solving. Default: 16M. Can safely increase to 100M.

  • Smallest resolved feature limited by grid dh

  • Memory: ~64 B per node

Equalization Steps#

Iterative smoothing after SDF/field definition.

  • 300: acceptable

  • 500: better

  • 1000: optimal Downstream solvers have unique quality sensitivities.

Sizing Parameters#

Net element size = distance × curvature effects.

  • Smallest relative length: 1.0

  • Largest relative length: 3.0–10.0+

Distance#

Monotonic sizing based on SDF. Higher density near surface, lower in farfield.

  • distance size ratio: 3–10

  • distance decay rate: 2–4 (standard deviations)

  • distance supra-exponent: 1 (exponential) or 2 (Gaussian)

Curvature#

Monotonic sizing for negative curvatures. No effect for positive curvature.

  • curvature size ratio: 2–3

  • curvature decay rate: 2–4

  • curvature supra-exponent: 1 or 2

Hexahedral Mesh#

Right-click → New → Hex Mesh. Specify:

  • Domain min/max bounds

  • Baseline grid resolution

Execute Job#

Press Submit to queue the job. The Job Manager appears. Press the green arrow to execute.

  • SDF solving may take 1–2 minutes for complex shapes/high resolutions.

  • Progress indicator tracks completion. Generated mesh appears in-scene.

Batch Process#

Headless mesh generation via command line:

./xcompute-server --batch onething.stl anotherthing.obj ...

Available options:

  • --estimate: Predict job time

  • --interior / --exterior: Domain selection

  • -x -y -z: Symmetry planes

For full options: ./xcompute-server --batch --help