Aspect ratio refers to the relationship between the width and height of a mesh element. When the aspect ratio is too high, the tetrahedron (tetra) may be flat or distorted, which affects the accuracy of the results.
Tetrahedra (tetra) with a high aspect ratio are detected with the
Mesh Statistics:
().
They can also be detected with the
3D Mesh Repair Wizard:
().
Description
The mathematical analysis of a model is based on the assumption that the mesh elements are uniform, equilateral tetras. In practice the mesh tetras range from ideal equilateral tetras to extremely distorted ones that adversely affect the results. As such it is important to reduce the number of distorted tetras as far as practical. Aspect Ratio is the most common method used to measure the mesh quality. Other methods are Internal Long Edges and Tetra with Extreme Angles between Faces.
It is particularly important that you mesh sensitive areas such as gates, areas with large geometry changes, or gas channels (in a gas-injection simulation) with low aspect ratio elements.
Low Aspect Ratio tetra (top) and High Aspect Ratio tetra (bottom)
A perfect tetra with equal edge lengths has an aspect ratio of 1. A flat tetra has a ratio of infinity.
Keep the maximum aspect ratio below 30 in as much of the mesh as possible. The recommended maximum aspect ratio value is 50; the absolute maximum value is 500
Recommended action
Always check the aspect ratio of the mesh :
(). Use the
3D Mesh Repair Wizard:
() to repair the majority of these elements.