ReferenceAvailable

Free Tetrahedral

Fill selected solid domains with tetrahedral elements for finite-element analysis.

Where to find it

Mesh workspace; System → Mesh

How to use it

Build the geometry, choose the domains, select a preset, and use Maximum element size to resolve small geometric or physical features. Choose Build Mesh to apply the sequence.

Settings and initial values

Setting	Initial value	Meaning
Selection	`all`	all selects the applicable domains; otherwise use a named selection or the selection editor. The selected domains receive this volume generator and its local size target. Recheck selections after geometry changes.
FEA backend	`Netgen (Python)`	Netgen (Python) generates the tetrahedral mesh used by solution-driven adaptation. Choose a backend supported by your geometry; this setting does not select a GPU solver.
Mesh mode	`User controlled`	Automatic creates Free Tetrahedral groups from the built geometry, uses Netgen (Python), and resets maximum and minimum sizes to auto. User controlled retains the authored sequence. Switching to Automatic can replace manual setup; it is not solution-error adaptation.
Preset	`Moderate`	Very coarse through Very fine derive size targets from the geometry span. Selecting a preset resets Maximum element size and Minimum element size to auto and updates the Netgen grading, edge and curvature controls. Custom retains individually edited controls; it is not itself a length.
Base fineness	`1`	When Maximum element size is automatic, the preset-derived target is divided by Base fineness, using at least 1 as the divisor. A value of 2 halves that target. An explicit Maximum element size takes precedence; values below 1 do not coarsen the preset.
Maximum element size	`auto`	Enter a length, for example 2[mm]; compatible length expressions are converted to metres. auto uses the preset or backend geometry sizing. This is a size target, not an exact element count or a guarantee that every edge has that length. Explicit sizes take precedence over Base fineness.
Minimum element size	`auto`	Enter a length in compatible units, converted to metres, or use auto. For a named preset, auto derives this value as a fraction of the maximum size. It is a meshing control, not a guarantee that small geometric details or poor-quality elements are absent.
Grading	`0.3`	Use a finite positive dimensionless Netgen grading value. Smaller preset values request more gradual size transitions, which may require more elements between fine and coarse regions.
Segments per edge	`1`	This finite positive dimensionless Netgen edge-resolution parameter can be fractional; it is not an exact integer element count on every edge.
Curvature safety	`2`	Use a finite positive dimensionless Netgen curvature-resolution parameter. Finer presets increase it to provide more resolution around curvature; it is not a radius or a length.
Close edges	`false`	When false, the close-edge factor is omitted from Netgen so that a stored factor cannot silently enable this sizing rule. When true, Close edge factor controls the rule.
Close edge factor	`2`	This is a finite positive dimensionless Netgen factor, applied only when Close edges is enabled. It is not a physical gap width.
Check overlap	`true`	This boolean enables the native overlap check; it does not repair overlapping geometry or define a physical contact interface.
Check overlapping boundary	`true`	This boolean controls the native overlapping-boundary check; it does not repair duplicate faces or sew an open shell.

Result

Inspect the element distribution and counts before running a study.

Troubleshooting

A mesh can be valid but too coarse for your quantity of interest. Compare results on a finer mesh and check element/DOF limits before a large solve.