Category Archives: Bump Mapping

Bump Maps

One of my favorite 3D tools is called “bump mapping.” It’s a way of adding a lot of detail to an object without altering its basic geometry.  Let’s take a common object in a 3D scene, a brick wall. One would normally create a brick wall by creating a rectangular, wall-shaped object and then mapping a photograph of a brick wall on top of it. This looks sort of like the picture, below. There is a photograph of a brick wall, and there is the photo mapped onto a rectangular object. It’s OK, makes a pretty convincing brick wall, particularly in the background.

But to add more realism, you can add what is called a “bump map.” Bump mapping is a technique in computer graphics for simulating small bumps, indentations and wrinkles on the surface of an object. Actually modelling all of those tiny indentations would take forever and would consume a lot of computer memory. Bump mapping is a way of creating all those tiny surface details without actually changing the surface of the object.

Here, I’ve created a bump map for the brick wall, by making a black and white, high-contrast version of the brick wall, then inverting it so it is a negative image. Anything designated as white will appear to stick out, and anything designated as black will appear to recede.

Here I’ve applied the bump map. The difference is subtle, but if you look closely, you can see that highlights are now added to the tops of the bricks and shadows underneath. And the brick wall looks much more convincing. It really makes a difference in creating a convincing object or scene.

Here’s a scene with a lot of bump-mapped textures. You can see it adds a lot of seeming detail to a scene with relatively simple geometry. (You can see the animation of this scene here.)

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