MESH modules allows you to work with Quadratic Elements.
Quadratic Edge in not a straight but a broken line and can be defined by three points: first, middle and last. All more complex Quadratic Elements differ from ordinary ones in that they consist of Quadratic Edges.
To add a quadratic element to your mesh:
1. Select your mesh in the Object Browser or in the 3D viewer.
2. From the Modification menu choose the Add item and select one of the following:
To create any Quadratic Element specify the nodes which will form your triangle by selecting them in the 3D viewer with pressed Shift button. Their numbers will appear in the dialog box as Corner Nodes (alternatively you can just input numbers in this field without selection).The edges formed by the corner nodes will appear in the table. To define the middle nodes for each edge double-click on the respective field and input the number of the node. All edges and the object formed by them will be displayed in the Object browser. When all edges are defined you will be able to click OK or Apply button to add the element to the mesh.
Reverse button for Quadratic Edges switches the first and the last nodes. For all other elements it reverses the element.