Creating the volume of the prism

• First copy the octagon a distance of 50 units relative to the surface of the wheel, which is where the base of the prism will be located. In the Copy window, choose Translation and Lines. Since we want to translate 50 units, enter two points that define the vector of this translation, for example (0, 0, 0) and (0, 0, 50). (Make sure that the Multiple Copies value is 1).
• Choose Select and select the lines of the octagon. Press ESC to conclude the selection.

• Since the Z axis is parallel to the user's line of vision, the perspective must be changed to visualize the result. To do this, use the Rotate Trackball tool, which is located in the GiD Toolbox and in the mouse menu. (or press <Shift> key and drag the right-mouse button to rotate the view)

• Choose Geometry->Create->NURBS surface->By contour. Select the lines that form the displaced octagon and press ESC to conclude the selection. Again, press ESC to exit the function of creating the surfaces.

• In the Copy window, choose Translation and Surfaces. Make a translation of 110 units. Enter two points that define a vector for this translation, for example (0, 0, 0) and (0, 0, -110).
• To create the volume defined by the translation, select Do Extrude Volumes in the Copy window.
• Click Select and select the surface of the octagon. Press ESC. The result is shown in next figure.

• Choose the option Render->Flat from the mouse menu to visualize a more realistic version of the model. Then return to the normal visualization using Render->Normal.

 NOTE: The Color option in the Layers window lets you define the color and the opacity of the selected layer. This color is then used in the rendering of elements in that layer.