The 3D Process

3D graphics involves the creation of three-dimensional virtual worlds within the computer. It's like simulating a movie set in which we describe the "actors" and props in the scene, the placement of lights, the viewpoint of the camera, and for animation, changes (such as movement) in any of the above. 3D illustration uses the same process as 3D animation but simply generates static images.


During this initial phase we meet with the client to discuss design concepts, tradeoffs (for example, greater realism may involve greater cost), and obtain any artwork that may already exist (such as logos). Then we design the characters and sets and create storyboards to plan camera angles and action sequences.


Models are then built for objects that appear in the scene. The time required for this can vary greatly depending on the complexity of the object and the level of detail required in the final images. Creating a 3D version of a logo is generally much faster than creating an organic object such as a dinosaur. In some cases we are able to save the client money by reusing existing props from our digital backlot or by purchasing pre-made models if suitable ones exist.


Once a model's geometry has been built, we need to describe its surfaces. This can be as simple as specifying attributes such as color, shininess, transparency, etc. or more involved such as when we create custom texture maps (digital paintings) or use specialized software for things such as "growing" fur. Often, simple objects can be made to appear quite realistic by mapping stock photographs onto their surface (e.g. brick, wood, wallpaper).


Lighting a virtual 3D set is similar to lighting a real photographic set. We choose the type of lights (such as spot or diffuse), their placement, brightness, color, throw pattern, etc. Unlike real lights, we can also choose things such as whether or not the light casts a shadow and its type (more realistic shadows generally take longer to render) and even have "negative lights" that remove light from a scene. We also have fine control over physical simulations such as lens flare, volumetrics (things like "rays" seen through a smoke-filled room), caustics (things like swirly patterns reflected onto a wall near water surfaces), and radiosity (things like color bleeding seen when a white object is placed next to a brightly colored one).


Animation is the illusion of movement by small increments of change between still frames shown in rapid sequence. In traditional cel animation each frame is drawn by hand. In computer animation we can simply "tell" an object to move from one point to another (known as keyframes) over some period of time and allow the computer to generate all of the frames in between. However a fancy song and dance number requires a lot more keyframes than simply saying "start on this side of the stage and end up on the other". Thus the amount of time it takes to animate something is usually related to the complexity of the movement. Most any object can be animated including models, cameras and lights. In addition to animating position, many other attributes of a scene can be animated such as the color of an object, the point of focus of a virtual camera lens, or the brightness of a light.


Rendering is the process whereby the description of a scene is turned into an actual image, or for animation, a sequence of images. It is during this process that the resolution of the image is determined (for example, print generally requires vastly greater resolution than video). Depending on a large number of variables, the time it takes to render an image (i.e. a single frame) can vary from a few seconds to days. By carefully controlling factors known to increase render time, test renders can be performed in a fraction of the time of the final render.


Once a scene has been rendered, additional post-processing may be required such as compositing with live action (film or video). Sometimes better control can be achieved by rendering parts of a scene in different passes and later compositing them together. Also some effects can be more easily achieved or rendered faster in 2D than in 3D. Once the final images are assembled the result is output to the medium of choice such as film, video, or CD-ROM.


3D graphics is often an interative and interactive process in which we work closely with the client to insure the results are what they expect. Unlike other forms of art in which major changes to the appearance can require doing most of the work over, 3D allows us to make some changes quite easily and then simply tell the computer to re-render the scene. Therefore the above "steps" do not necessarily follow the order given.