Bump mapping: Realistic 3D texturing

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What is bump mapping?

Bump mapping is a software CGI technique for simulating texture on the surface of a 3D model without having to create each crack, crevice, bump, and other blemish tediously by hand. The bump map is a grayscale image file that creates the illusion of the 3D model’s surface going up or down by the level of black (down) or white (up) in each pixel.

Bump mapping helps 3D models look more realistic while saving the graphic artist time. Also, because the bump map does not alter the geometry of a 3D model, it keeps the asset’s file size lower.

Is a bump map the same as a height map?

Though bump maps and height maps are similar, a height map is a sub-type of bump map. A height map computer graphics raster image is often used in bump mapping to provide surface displacement data. Height maps were the original form of bump mapping invented in 1978.

However, a newer and more common method uses a normal map, which directly modifies each surface point from the norm. Because a normal map is more direct than a height map, the normal map method of bump mapping provides more detail and more predictable results and is often easier for artists to use.

Can you convert a bump map to a normal map?

Yes, you can convert a bump map into a normal map using a tool like NormalMap Online.

What is a bump map vs. a specular map?

Bump maps and specular maps are texture mapping techniques using grayscale images to control aspects of a surface’s appearance in computer graphics. A bump map contains height data in each pixel, where black is the lowest point and white is the highest point. This data simulates the look of surface bumps and textures without changing an object’s actual geometry.

A specular map contains data on how reflective a surface is at various points to create surface highlights, reflections, and shininess. In specular map grayscale images, white is highly reflective, while black is non-reflective (matte).