three axes are different, and, as a result, each axis is also foreshortened by a different amount. This results in a pretty distinct look that has a clear angular bias, e.g., a building pointing up-left will look quite a bit different from a building pointing up-right even if the two structures are identical.The advantages of Trimetric projection were clearly kept in mind by Maxis when the team was creating SimCity 4, and Paul Pedriana wrote a nice little article about it.A space-bending level in Crystal Castles, an iguana-on-a-stick vendor in Fallout, and a typical city in SimCity 4, all displayed via differently skewed Trimetric projections.As an interesting side-note, all Orthographic projections follow a strict set of rules, making them very easy to do in 3D games (provided that the camera is locked at a specific angle).2). Oblique ProjectionOblique projections are actually very similar to their Orthographic counterparts. Both techniques utilize parallel rays, but with one small difference: Orthographic rays hits the canvas at perpendicular angles, i.e., 90 degrees, whereas Oblique rays hit the canvas at angle between 0 and 180 thats not 90 degrees. This results in completely arbitrary scaling of dimensions and angle proportions. Simply put, Oblique projections are not sticklers for rules, and the resulting images often appear distorted, e.g., a sphere projected obliquely will appear as an oval.Due to this stretching out effect, Oblique projection hasnt been very popular in games. It has all the disadvantages of Orthographic projection, and it tends to generally look more awkward. Still, an Oblique projection can create a unique appearance, and one if its sub-types, Cabinet projection, has enjoyed some success in videogames.Cabinet projection relies on first drawing one side of an object as it would appear looking directly at it (without any scaling or rotation). Once the full side is rendered, the other two sides are extended away from it in any direction, usually at a 45 degree angle. The lengths of these sides are also cut in half to help simulate a sense of depth. Its a fairly simple approach that uses a simple, easy to remember ruleset. It was also first popularized in furniture illustrations, hence the name.Pac-Mania, Ultima VII, and Earthbound, three games that looked a bit odd at times, but generally benefited from using Oblique projection.3). Perspective ProjectionAn example of how light rays are projected using Perspective projection.Unlike the above two projection types, Perspective projection relies on the concept of a focal point. The cameras angle and position dont really matter as the entire scene recedes out into the distance (the horizon when looking straight out, the earths core in a birds eye view, etc.). This is how actual cameras work, which, in turn, are designed to emulate the functionality of the human eye.In art, there are various ways of doing Perspective projection via vanishing points (visit Scott McDaniels site for a pretty thorough overview). These are somewhat artificial, though, as they rely on approximations where straight lines are not available.Battlezone, an old, vector-based arcade game that used Perspective projection.Early 2D adventure games followed this approach by using