Behind you!

In 3D computer graphics it’s vital to be able to produce realistic looking images. Scenes are often created by arranging 3D shapes in the right pattern. The problem is that sometimes this means that parts of things behind should be hidden by parts of things in the front. Calculating the geometry over which bits of objects are covered isn’t easy.

There is a simple way to solve the so-called ‘hidden surface’ problem though: the Painter’s Algorithm. The computer acts like a simple, but orderly artist who paints the distant parts of a scene first and then splashes on more layers of colour, covering the background by painting those parts that are nearer giving a simple, but often effective, image.