Computer graphics pipeline

Computer graphics pipeline is the process that goes from an idea to the fully realised 3D model. This process incorporates six phases: pre-production, 3D modelling, shading and texturing, lighting, animation and rendering and post-production. Pre-production phase includes all of the sketches, paintings, colour palette and details of the 3D model. When the model concept is ready, a 3D modeller translates a 2D drawing into 3D model. There are two major techniques for modellers: polygonal modelling and digital sculpting. Polygonal modelling is suited for architectural modelling, while digital sculpting for organic modelling. The next step in the pipeline is the shading and texturing phase where colours, materials and textures are added to the 3D model. In the lighting phase, digital light is added to the 3D scene to illuminate models. Then, animators have to bring to life 3D characters and environment. There are two animation techniques: Rigged for Motion and Pose-to-Pose. The first technique incorporates virtual skeleton which controls the motion of the model. The second one incorporates a set of key-frames with different poses of the model which will create the illusion of motion. The final phase incorporates finalising shadows, adjusting colours, brightness or contrast as well as integrating special effects to the scene.

Two Examples of Existing 3D Films

A Bug’s Life

A Bug’s Life is 3D computer-animated comedy-adventure film produced by Pixar Animation Studios, directed by John Lasseter. The story is about an ant Flick who is looking for strong warriors to save his colony from greedy grasshoppers. This 3D animation is based on Aesop’s fable ‘The Ant and the Grasshopper’ and released to the cinema in 1998. The ants were redesigned by Pixar to be more appealing.

All of the phases in the pipeline were followed by the Pixar team members. The film concept was changed several times to be more original than previous approaches. There were some challenges during the animation phase because of the models’ complexity. In order to present the world of the insects’ perspective, there was done primary and secondary research. It was created a miniature video camera on Lego wheels which could roll through different terrains such grass and explore insects’ world. The secondary research incorporates watching a French documentary Microcosmos which explores insects’ life. In order to present characters of the story more likable, designers gave away from natural realism. Six legs of the ant were replaced by two legs and two arms. The grasshopper gained a pair of extra appendages. Some of the shots of the animation included crowds of 400 or 800 ants. It is impractical for animators to control individually each ant. This problem was solved with animating 4 groups of ants with 8 individuals in each group. Then, each of these ants was randomly distributed to scene. The software helped each ant to gain different characteristics such as its own colour of the clothes, skin or different weight. Thus, all of the ants differ from each other. It was used for the first time in Pixar subsurface scattering, which is a mechanism of light. This is necessary for realistic rendering of materials. There was, also, a voice casting where most of the television stars were chosen to play characters of the story. It was created an original soundtrack album labeled as A Bug’s Life: An Original Walt Disney Records Soundtrack. The album contains twenty songs written and composed by Randy Newman. The target audience is both children and adults. Children enjoy watching creatively designed characters as well as the adventure of the animation. Adults appreciate the skillful animation along with its humor.

Monsters, Inc.

Monsters, Inc. is a 3D computer-animated comedy-adventure film produced by Pixar Animation Studios. The story is about two monsters, James P. Sullivan known as Sully and one-eyed Mike Mazowski, who work for a company named Monsters. Monsters generate their city's power by scaring children, but they are terribly afraid themselves of being contaminated by children, so when one enters Monstropolis, Sulley finds his world disrupted.

Production process of this animation encompasses five years from 1996 to 2001. During those five years, it passed through many changes and challenges. All of the phases in the pipeline were followed by the Pixar members. Peter Docter’s initial concept of the film passed through many changes. His initial idea revolved around a 30 year old man dealing with monsters which represent his fears. When the man conquers his fears, the monsters disappear. Then, Docter developed a story about a child and a monster. The monster Sulley works in a company which purpose is to scare children. Later, the story includes the monster Mazowski. The child varied in age and gender. When the script was ready along with the character design, 3D modellers and animators start working on the film. Each main character had its own lead animator. Sulley’s leading animator John Kahrs enabled his character to move fast in spite of its heaviness. This Sulley’s characteristic made him more attractive for the audience. John Karh was helped with his animation of the big monster. Rodger Kram, an expert at Berkeley, came to lecture on the subject about heavy mammals. There was a problem with rendering the fur of Sulley as it required realistic appearance. Another challenges were related to efficient rendering of a huge number of hairs, 2 320 413 on Sulley as well as making sure that the hairs cast shadows on other hairs. Because of the extreme motion of Sulley, its fur stretched and intersected with other objects. All of these problems were solved with the creation of simulation software called Fitz. The program allowed the fur to react in a natural way during Sulley’s movements and wind. It, also, took into consideration gravity effects. To solve the problem cloth-to-cloth intersection, Pixar scientist Michael Kass developed an algorithm known as “global intersection analysis”. There was held voices casting where were chosen famous comedians to play the characters. One of the was John Goodman co-star of the comedy series Roseanne and a regular in the films of the Coen brothers. The target audience is both children and adults. Children enjoy watching creatively designed characters as well as the adventure of the animation. Adults appreciate the skillful animation along with its humor.