2D Versus 3D Animation

There are two fundamental types of animation that you might consider using when creating games : 2D and 3D. 2D animation involves objects moving or being manipulated within two dimensions. Objects in a 2D animation can still have a 3D look to them ”they just can't physically move in three dimensions. Many 2D animation techniques simulate 3D animation by altering the look of objects, but they aren't truly 3D. As an example, an animation of a car driving off into the distance would involve the car getting smaller as it gets farther away. However, this isn't necessarily a 3D animation because you can achieve the 3D effect by making the car image get smaller as it moves away. Although the end result is three-dimensional, the car is very much a 2D object.

Unlike 2D animation, 3D animation involves placing and manipulating objects in a three-dimensional virtual world. A 3D object is defined by a model rather than an image because an image is inherently two-dimensional. A 3D model specifies the shape of an object by a series of points in 3D space. In other words, a 3D model is a mathematical representation of a physical object. For this reason, 3D graphics and animation can get extremely complicated because it often relies on heavy-duty mathematical processing.

In reality, many games make use of a mixture of 2D and 3D graphics and animation. For example, the original Doom game uses 3D graphics for the building interiors. However, the monsters in the game are 2D graphics objects. The monsters have a 3D appearance, but they are represented by flat images on the screen. This mixture of 2D and 3D graphics works great in Doom because the 2D monsters look realistic when blending into 3D surroundings. Of course, things have evolved since the original Doom game. Quake and other more modern 3D first-person shooters (FPS) now use 3D objects throughout the game.

The remainder of this hour , and the book in general, focuses on 2D animation because it is the more straightforward and efficient technique of the two. The good news is that you can still do some pretty powerful things with 2D animation.