© 2001 Winston Mitchell
A bump map is a gray scale image; any image will do. The lighter areas are rendered as raised portions of the surface and darker areas are rendered as depressions. The bumping is sensitive to the direction of light sources. If the transition between light and dark areas is a gradient, the gradient will render as a slope.
Very striking effects can be achieved by combining an ordinary image used as a pattern map using "Wrapped Image" on the Pattern Tab and a grayscale version of the same image as a "Wrapped Bump Map" on the Texture Tab. Optionally, the bump map can be softened or otherwise fiddled with using Paint Shop Pro or some other graphics tool.
The image to the left above is the bump map I used for the "Yard Art" image (to the right). It started out as a TurboCAD 2D drawing and was copied into Paint Shop Pro. There it was blurred and some noise was added to get the pits. If you are drawing in inches and map it to the z-plane of a large surface with a scale of 900 you will get a reasonable representation of the 9" by 5½" pavers commonly sold at home centers.
If you want to use this bump map, use your browser to save it as "Pavers.bmp". If you save it as a GIF file, TurboCAD won't recognize it as a bump map.
NOTE: You can use jpegs for pattern maps and bump maps in TurboCAD but I do not recommend them for bump maps because the subtle compression artifacts can produce a very noticeable texture of their own.