h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

My eyes glazed over reading the entry , but it does remind me of a handy application in 3D computer modelling. Using Boolean properties for 3D meshes can be an interesting way to generate new shapes. For example, there is a well known 3D program named "Bryce 5" that allows creating skies, landscapes, trees, etc., then rendering the scene as a still image or an animation. Elaborate models of buildings, cars, ships, etc. can be imported, but there are no modelling tools for creation of such items. The program does have some "primitive shapes" - spheres, cones, boxes, etc. - and supports Boolean combinations of those shapes.

A simple example - I had a flat ground plane and needed to show some (imported) stairs going underground, but the ground plane "covered" the stairs. So I added a box, made it negative and protruding through the positive ground plane, fitting the size to the stairs. I then grouped the plane and the box and voila!, a rectangular hole in the plane showing the (non-Boolean) stairs. The box was invisible during rendering. A handy item with Bryce, in lieu of modelling tools.

In addition to positive and negative, the Boolean property can be set to "intersect", so only the portions of the two items that intersect will render. There are some pretty weird shapes floating around in the Bryce world.