.. _add_node_on_segment_page: ***************** Cutting triangles ***************** This operation cuts triangles into two by adding a node on an edge bounding these triangles. .. image:: ../images/add_node_on_segment.png :align: center *To cut triangles:* .. |img| image:: ../images/mesh_split_diag_interactive.png #. Select a mesh and display it in the 3D Viewer. #. In the **Modification** menu select the **Add node on segment** item or click *"Add node on segment"* button |img| in the toolbar. The following dialog box will appear: .. image:: ../images/add_node_on_segment-dlg.png :align: center #. Enter IDs of nodes forming the edge in the **Edge** field (the node IDs must be separated by a dash) or select the edge in the 3D viewer. #. Enter location of a new node on the edge which is defined as a real number in the range between 0.0 and 1.0. You can define it * by clicking with your mouse on the edge in the Viewer, * by typing a number in a field, * by setting a number using arrows of a spin box. #. Activate **Preview** to see a result of the operation. #. Click the **Apply** or **Apply and Close** button to confirm the operation. **See Also** a sample TUI Script of a :ref:`tui_cutting_triangles` operation.