.. _aspect_ratio_page: 

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Aspect Ratio
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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:**

#. Display your mesh in the viewer.
#. Choose **Controls > Face Controls > Aspect Ratio** or click	**Aspect Ratio** button in the toolbar.
                         
   
	.. image:: ../images/image37.png
		:align: center

	.. centered::
		Aspect Ratio button

	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` operation.