+.. _aspect_ratio_page:
+
+************
+Aspect Ratio
+************
+
+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).
+
+
+* The **Aspect Ratio** of a **triangle** 2D element consisting of 3 nodes is calculated by the formula:
+
+ .. image:: ../images/formula4.png
+ :align: center
+
+* 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:
+
+ .. image:: ../images/formula5.png
+ :align: center
+
+*To apply the Aspect Ratio quality criterion to your mesh:*
+
+.. |img| image:: ../images/image37.png
+
+#. Display your mesh in the viewer.
+#. Choose **Controls > Face Controls > Aspect Ratio** or click *Aspect Ratio* button |img| in the toolbar.
+
+ Your mesh will be displayed in the viewer with its elements colored according to the applied mesh quality control criterion:
+
+ .. image:: ../images/image94.jpg
+ :align: center
+
+
+**See Also** a sample TUI Script of an :ref:`tui_aspect_ratio` filter.
