The Displace tool uses a bitmap image to define a translation for the control points of the selected NUBS meshes. You can use the tool to create real bumps to mesh surfaces (the material bump mapping modifies only the shading of the surfaces, not the geometry).
The following example shows how to use the tool.
1. Go to the NURBS tool tab. Activate the Rectangle tool.
2. Define a suitably high resolution for the mesh in the tool control bar. The displacement tool displaces the existing points of a mesh, so only a dense mesh can represent bumps defined by typical image resolutions. We will use a low-resolution image, so U=50 and V=50 should suffice for our test.
3. Finish the Rectangle tool by drawing a square mesh in a view window.
4. Make sure the mesh is selected. Go to the NURBS tool tab and activate the Displace tool.
5. Define a suitable maximum height for displacement using the Displacement field in the tool control bar, for example 0.1 meters.
6. Browse a suitable image file to the Image field, for example 'textures/logo_bw'. Now the program computes the displacement and you can see the result in the view window. Adjust the height if necessary. Then click Accept to finish the tool.
The result is shown here as a ray traced image. The 'brushsteel' material was slightly modified and mapped to the displaced surface to make it appear more interesting.