Surface Remesher Reference

• Triangle: Creates the surface mesh using triangles.
• Enhanced Quality Triangle: Generates triangle surfaces of higher quality. When activated, it provides the following advantages:
  • Alignment with curvature and boundaries (feature edges, part boundaries). Enhanced quality triangles are better at capturing the geometry and are closer overall to the input geometry.

    注	Alignment is only feasible when sizes aren't changing on a surface. In cases where they change, the alignment must be sacrificed to allow for the change in mesh size.

  • Allows you to better capture target sizes coming from inputs such as curvature size, surface proximity and base sizes.

  However, the improved quality of the triangles increases the CPU time in generating the mesh. You are advised to only use this option as a local control for surfaces where quality and alignment are most needed.

• Quad Dominant: Creates the surface mesh using quadrilaterals with the same characteristics listed above for the Enhanced Quality Triangle mesher. If you use either a Tetrahedral or Polyhedral mesher with the Advancing Layer Mesher, you can use both isotropic and anisotropic quadrilaterals. However, if you use either a Tetrahedral or Polyhedral mesher with the Prism Layer Mesher, only isotropic quadrilaterals are available. Do not use the quad dominant method on coarsely resolved geometry.

This option is similar to proximity refinement. Proximity refinement specifies a mesh size that is based on the gap size and the number of points inside the gap. Whereas, compatibility refinement ensures that the mesh size on either side of the gap is similar. In some cases, this results in fewer elements and a more efficient use of the surface remesher.

For example, consider the surface mesh below. The curvature of the cylindrical pin reduces the mesh size near the pin:

Applying compatibility refinement has the following effect on the surface mesh opposite the cylindrical pin due to the presence of square hole on the base of the thin flat plate:

As can be seen above, the surface mesh in the region opposite to the cylindrical pin is refined, as the compatibility refinement makes the mesh size across the gap similar to the mesh of the hole. Note that the surface growth rate also influences the mesh size, so the sizes are not identical. The refinement on the surface mesh in turn affects the volume mesh by creating refined and better quality cells in the gap between the pin and opposing surface.

• An aligned mesh reduces the overall surface mesh quality.
• The aligned meshing conditions are not met.
• The underlying geometry is not suitable for aligned meshing.

The Create aligned mesh option is a property of the Surface Remesher meshing model, and is activated by default. Use the checkbox to deactivate aligned meshing. The following example illustrates the effect of the Create aligned mesh option. The blue sections highlight CAD edges for comparison between this surface mesh and those in the previous section.

Currently, the following conditions apply to the Create Aligned Meshes option:

• Aligned sections must have 4 sides and have geometric features as closed boundaries, for example:

  
  

  

  
  
• There must be less than a 30% difference between the number of vertices that the surface remesher creates on opposing sides of an aligned section.
• The remeshed surface must have a relatively uniform surface mesh size. As a general guideline, the minimum surface size (without aligned meshing) must be greater than half of the maximum surface size.
• Aligned meshes cannot lie on a periodic interface boundary, or be connected to one along an edge (in-place interfaces are supported).
• Aligned sections cannot contain inner loops, such as an inlet duct on a filleted edge:
  
  
  
  

The quality of a triangular face is defined as:

where $R$ is the radius of the circle that passes through the three corner points of the triangle and $r$ is the radius of the circle inscribed in the triangle. A value of 0 represents a degenerate, zero area face and 1 represents a face with perfect face quality.

To achieve the minimum quality, Simcenter STAR-CCM+ is allowed to modify part curves to improve or remove faces whose quality is below the specified value.