Understanding the tetrahedral meshing process

The software uses the following process to generate a tetrahedral mesh:

1. The software abstracts the selected polygon geometry to remove small surfaces or edges that may cause problems during meshing. The software bases this abstraction on the specified Element Size in the 3D Tetrahedral Mesh dialog box.

2. The software creates the surface mesh domain. This is the process by which the software parametrizes the polygon faces and prepares to mesh them in 2D space.

3. The software generates a mesh of triangular 2D (shell) elements on all surfaces in the model. When the software completes this surface triangulation process, the progress meter indicates that the overall process is approximately 66% complete. See Details of the surface meshing process for more information.

4. The software uses the triangular elements to generate 3D (solid) elements throughout the model.

5. If you are creating a mesh of parabolic tetrahedral elements, the software inserts the midside nodes.

6. The software checks the quality of the solid elements and attempts to fix quality issues wherever possible.

7. The software associates the mesh with the underlying polygon geometry.

8. The software generates the display of the completed mesh in the graphics window.

Details of the surface meshing process

The software performs a number of checks to ensure that it can generate a solid mesh from the generated surface mesh. A number of different problems can occur during surface meshing. Typical problems include:

• Surfaces on which the software cannot generate a 2D mesh

• Free surface element edges.

• Triangular elements on different surfaces that either intersect or penetrate each other.

• Boundary recovery failures. These can occur when the surface meshes are grossly different through a thickness in a confined area. Significant differences in surface meshes can prevent the software from being able to generate solid elements that can properly connect to the surface elements.

If the software identifies problems with the surface meshing, it reduces the displayed degree of completion in the progress meter to 60%. It then tries to repair any existing issues with the surface mesh by remeshing problem areas (the affected faces and any neighboring faces) with smaller element sizes. If this does not resolve the issues, the software deletes the problem mesh and any neighboring meshes and then remeshes them all with smaller element size. The software continues to iteratively remesh problem areas with smaller element sizes.

How do I

Create a 3D tetrahedral mesh

Learn more

3D tetrahedral meshing

Understanding 3D tetrahedral mesh quality evaluation

Midnode placement for parabolic elements

Creating at least two elements through the thickness of tetrahedral meshes

Understanding the Auto Fix Failed Elements process

Controlling the size of interior elements in a 3D tetrahedral mesh

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Understanding the tetrahedral meshing process, Simcenter 3D 2021.1 Series

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