How does animation compare?
When we talk about animation, there are a range of different techniques to choose from. Many of these techniques can be used alone, or combined to create a finished product. The techniques available to animators can result in an enormously diverse range of animated output – from a simple cartoon to a character in a live action film.
Traditional Animation and CGI
Traditional animation involves the use of physical tools, materials and processes, whilst CGI takes place in a virtual space, using digital tools, materials and processes.
Whilst many traditional animations are filmed using digital techniques, what categorises them as traditional animation is the way the animation itself is produced. For example, cel animation involves each frame being hand-drawn and hand-painted onto physical cels. Stop motion involves the physical manipulation of objects, such as clay models, which are then photographed frame by frame. This technique is used to great effect in the Wallace and Gromit films and Creature Comforts series by Aardman Animations.
CGI can involve the manipulation of traditional 2D animation within a virtual environment, or the entire process can be recreated on computer, with the original drawing created using computer software. Computer software can also be used to perform traditional techniques, such as painting, directly onto a computer image.
Creating 3D animation
To create 3D animation, objects are modelled on computer software and characters are rigged with a virtual skeleton. Each frame must be rendered with features, such as shading, texture and reflection to produce a 3D effect.
Sophisticated computer software can be used to create interactive environments and virtual crowds, using CG animation and artificial intelligence. Examples can be found in the epic battle scenes of films like The Lord of the Rings and Troy.
CGI character animation
For animating characters most 3D computer animation systems will use a skeletal model defined by a number of animation variables (or avars). These control the position of a particular part of an animated character, for example the limbs and face. Avars can be manipulated to produce movement and expression in the character, like a marionette. In the original ‘Toy Story’ film, Woody had over 700 avars, over 200 of which controlled his face alone.
Disney and CGI
In 2005 Disney announced that ‘Home on the Range’ would be its last 2D traditional animated film. Later that year it released ‘Chicken Little’, the studio’s first fully CGI animated feature film. In 2006 the Walt Disney Company bought Pixar Animation Studios for $7.4 billion, indicating a new commitment CGI animation. New Chief Creative Officer John Lasseter, however, decided to revive the classic fairytale with a return to traditional animation techniques in ‘The Princess and the Frog’ in 2009.
In 2013 Disney released what became the highest-grossing animated film of all time, ‘Frozen’. This was entirely animated in 3D CGI.
CGI animation can be applied to create visual effects post-production. There are many different categories of visual effects, such as using still images as backgrounds for rotoscoped elements, filming actors against a green screen, adding digitally animated characters, or digitally enhancing environments. For example, CGI visual effects were used to recreate the storm scene and the tiger in The Life of Pi. Green screening was used in Harry Potter and the Deathly Hallows to digitally insert the burning castle environment at a later stage. The first Matrix film used a technique known as ‘bullet time’ where a series of cameras circling the subject of the scene are triggered simultaneously to capture the action of the scene whilst providing a slow motion effect. Computer technology was used to edit out the cameras and replaced them with 3D-modelled backgrounds based on photographs of the surrounding buildings.
Motion capture uses live footage to apply movement to an animated character. In this case an actor will perform the scene and their body movements are recorded to computer. This technique was used to animate the body of the creature Gollum in The Lord of the Rings. For Gollum’s facial expressions motion capture was considered but not used – instead they were entirely keyframed. A digital puppet of Gollum’s face was created to model the facial expressions and the animators added textures and shading. The lead animator created a series of ‘combination sculptures’ that acted as keyframes. A keyframe is a frame that defines the beginning and end of a transition. The frames between each keyframe are known as ‘inbetweens’. Inbetweens ensure the smooth transition from one keyframe to the next and help to create the illusion of motion.