# Cutting quadrangles

This operation allows to cut one or several quadrangle elements by addition of a supplementary edge which will connect two opposite corners.

To cut quadrangles:

1. Display a mesh or a submesh in the 3D viewer.

2. In the Modification menu select the Cutting of quadrangles item or click button in the toolbar. The following dialog box will appear:

- The main list contains the list of quadrangles. You can click on an quadrangle in the 3D viewer and it will be highlighted (lock Shift keyboard button to select several quadrangles). Click Add button and the ID of this quadrangle will be added to the list. To remove a selected element or elements from the list click Remove button. Sort list button allows to sort the list of IDs. Filter button allows to apply a definite filter to the selection of quadrangles.

- Apply to all radio button allows to modify the orientation of all quadrangles of the currently displayed mesh or submesh.

- Preview - provides a preview of cutting in the viewer.

- Criterion

- Use diagonal 1-3 and Use diagonal 2-4 allows to specify the opposite corners which will be connected by the cutting edge.

- Use numeric factor - allows to apply the operation only to those objects which meet the chosen criterion (from the list of Quality Controls, i.e. Skew, Warping, Minimum Angle, etc.)

- Select from - allows to choose a submesh or an existing group whose quadrangle elements will be automatically added to the list.

3. Click the Apply or OK button to confirm the operation.

See Also a sample TUI Script of a Cutting Quadrangles operation.