# Aspect ratio 3D

The Aspect Ratio 3D mesh quality criterion calculates the same parameter as the Aspect ratio criterion, but it is applied to 3D mesh elements: tetrahedrons, pentahedrons, hexahedrons, etc.

- The Aspect Ratio of a tetrahedron 3D element is calculated by the formula:

,

where S K is the sum of surfaces of the faces of К and V K is the volume of К :

T

- Other element types like quadrangle, pentahedron and hexahedron use the following formula:

, where Q i represents the value of Q k for all possible simplexes (of the same dimension as the element) that compose the element.

For example, a hexahedron is split in 6 tetrahedrons, the Aspect ratio 3D is calculated for each of them, then the greatest Q k is considered to be the Aspect ratio 3D criterion for the whole hexahedron.

To apply the Aspect Ratio 3D quality criterion to your mesh:

1. Display your mesh in the viewer.

2. Choose Controls > Aspect Ratio 3D or click button of the toolbar. Your mesh will be displayed in the viewer with its elements colored according to the applied mesh quality control criterion:

See Also a sample TUI Script of an Aspect Ratio 3D quality control operation.