How Is Computer Animation Made?by Daniel Ketchum
Animation has been one of the most popular film genres since the early days of cinema. At one time these animations were based on hand-drawn cells for each frame of the film. These days, animation has largely come to be dominated by CGI, or computer-generated imagery. While some computer animation also is created frame by frame by hand (or mouse), the vast majority is made using 3-D models, which are posed across a series of frames and rendered. There are several key parts to the animation process.
The process of creating animation begins by storyboarding out on paper the scenes you want based on the script. Essentially, storyboarding involves creating pages of comic strips, illuminating the action in the various scenes. This provides a visual reference for the other parts of the process.
In modeling, the 3-D figures, structures, props and background scenes are created on a modeling program. These models are mathematically based polygon meshes. Each is shaped to resemble the figure or object that is needed. An important part of modeling is making sure that you create meshes that contain only as many polygons as you need for the mesh to do its job in the scene. For a simple object like a book, you might be able to get away with just a few. But with a complex figure like a person who has to be posed, you might have tens of thousands of polygons.
UVmapping and Texturing
Once the 3-D model meshes are created, they have to be UVmapped and textured. First, the modeler defines seams in the model along which it can be divided. The model is not literally divided, however. Instead the seams define where a texture map placed on the model should be placed. Then the texture map itself is created by painting onto a 2-D map based on the UVmap, or by painting directly on the model. This texture map serves as the colored "skin" of the model. Without this skin, the model would look like a lifeless mass.
If the model is one that has to be pose-able (like a person, dog or folding table) then it will have to be rigged. In the rigging process, the body parts of the model are defined as "groups," with all the polygons in an area being assigned to a group such as "larm" or "rthigh."
When all the elements for the animated scene are ready, they are loaded into whichever animation program is being used. Each is placed in the scene, lighting is added, and then the posing tools are used to pose the figures across a series of frames in the timeline (based on the storyboard). Finally, these frames are rendered out as animation.