Animation is the process of rendering images in quick succession so as to give an impression of continuous motion. In 3D animation, the images that are used are three dimensional. They can be shown from all possible directions, are made to adhere to natural physics laws, and therefore appear exceedingly real to the viewers.
There are many different types of three dimensional animation. Some of the main ones are stop motion animation, claymation, computer generated imagery (CGI) and motion capture animation. These animations are done using hand-crafted as well as computer-generated puppets, objects, backgrounds and special effects.
In stop motion animation, the 3D characters and their backgrounds are designed by hand. First the animator makes an armature or skeleton using metal and then fashions the objects on this using clay, plastic or rubber. Different materials like wood, cloth, hair gel, toothpaste and cotton wool may be used to create finer details.
The handmade objects are arranged in a scene and a photograph is taken. Then the objects are moved slightly and photographed again. After photographing the objects every time their position is altered, the animator uses the photographic frames to create the 3D animation.
Claymation is a stop motion animation using clay models. The clay is worked on over an aluminum wire frame and shaped with fingers and clay tools. To prevent the sculpted figures from being misshapen in handling, a quick hardening clay is used. Once it has dried, the figures are painted as required.
The use of computers has, in many ways, revolutionized the three dimensional animation. Animators are no longer required to draw, sculpt or color everything by hand. By switching to the digital medium, the entire 3D animation process can be carried out in a faster, less cumbersome and more cost-saving manner.
So much so that CGI is also used in non-animated movies. The computer graphics create scenes that might have otherwise been very expensive or difficult to produce. Some scenes would be even impossible to create without computer generated imagery.
In computer generated 3D animation, the animator builds virtual skeletons and models 3D figures over them. Then the digital models are rigged and can be manipulated as required for the animation. The animator must take care to get all the physical movements and details right so that the 3D animation looks real.
Motion capture animation goes a step further and makes use of live action. Here, an actor is outfitted with sensory devices that plot the movement and positioning of the actor's joints. The actor then goes through the motions in place of an already designed character that is to be animated.
The sensory devices record the resulting motions and transmit the video-recording into a computer. The computer now uses these inputs to give movement to the character. This brings motion capture animation as very close to movments seen in real life.
Some well-known animated films are Shrek, Finding Nemo, and Wall-E. 3D animation films are becoming more and more inclined towards realism. The next step is to use computer graphics to create an entirely photorealistic 3D animation film.