7 The **Aspect Ratio** quality criterion for mesh elements reveals the degree of conformity of a mesh element to the regular element of its type (with all edges having the same length).
10 * The **Aspect Ratio** of a **triangle** 2D element consisting of 3 nodes is calculated by the formula:
12 .. image:: ../images/formula4.png
15 * The **Aspect Ratio** of a **quadrangle** 2D element consisting of 4 nodes is calculated using The Verdict Geometric Quality Library available within VTK. The calculation formula is:
17 .. image:: ../images/formula5.png
20 **To apply the Aspect Ratio quality criterion to your mesh:**
22 #. Display your mesh in the viewer.
23 #. Choose **Controls > Face Controls > Aspect Ratio** or click **Aspect Ratio** button in the toolbar.
26 .. image:: ../images/image37.png
32 Your mesh will be displayed in the viewer with its elements colored according to the applied mesh quality control criterion:
34 .. image:: ../images/image94.jpg
38 **See Also** a sample TUI Script of an :ref:`tui_aspect_ratio` operation.