Bump maps are images that are applied to 3D models to produce the appearance of bumps, grain, or ridges on the surface of the object. The reason for doing this is that it avoids having to actually model these features into the 3D object during the modeling process. It also reduces the render time by minimizing the number of polygons on the object.
1. Open Photoshop. Select “File” and click “Open.” Browse to the texture file you want to create a bump map for. A brick texture will be used for this example. Brick and other textures are freely available online (see Resources).
2. Select “Image,” then “Mode” and click “Grayscale.” Click “Discard.” Then select “Image,” then “Adjustments” and click “Brightness/Contrast.” In the dialog that opens, adjust the brightness and contrast sliders to produce the maximum contrast in your image. The exact number will depend on your image.
3. Select “Filter,” then “Blur” and click “Gaussian Blur.” In the Gaussian dialog that opens make the “Radius” about 5 and click “OK.” Now save your bump map as a BMP file.