-.. _uniting_set_of_triangles_page:
-
-**************************
-Uniting a set of triangles
-**************************
-
-It is possible to unite many neighboring triangles into
-quadrangles by deletion of the common edge.
-
-*To union several triangles:*
-
-.. |img| image:: ../images/image80.png
-
-#. Select a mesh (and display it in the 3D Viewer if you are going to pick elements by mouse).
-#. In the **Modification** menu select the **Union of triangles** item or click *"Union of triangles"* button |img| in the tool-bar.
-
- The following dialog box will appear:
-
- .. image:: ../images/a-unionoftriangles.png
- :align: center
-
-
- * **The main list** shall contain the triangles which will be united. You can click on a triangle in the 3D viewer and it will be highlighted. After that click the **Add** button and the ID of this triangle will be added to the list. To remove a selected element or elements from the list click the **Remove** button. The **Sort** button allows to sort the list of IDs. The **Filter** button allows to apply a definite :ref:`filter <filtering_elements>` to selection of triangles.
- * **Apply to all** radio button allows to apply the operation to all triangles of the selected mesh.
- * **Preview** provides a preview in the viewer.
- * **Criterion** menu allows to choose a quality criterion, which will be optimized to select triangles to unite.
- * **Select from** set of fields allows to choose a sub-mesh or an existing group whose triangle elements then can be added to the list.
-
-#. Click the **Apply** or **Apply and Close** button to confirm the operation.
-
-If some selected triangle elements have no adjacent edges with one of
-the others, the operation on these elements shall take no effect.
-
-.. image:: ../images/uniting_a_set_of_triangles1.png
- :align: center
-
-.. centered::
- The chosen triangles
-
-.. image:: ../images/uniting_a_set_of_triangles2.png
- :align: center
-
-.. centered::
- The union of several triangles - several quadrangular cells are created
-
-**See Also** a sample TUI Script of a
-:ref:`tui_uniting_set_of_triangles` operation.
-
-