Scripting Systems were the earliest type of motion control systems. The animator writes a script in the animation language. Thus, the user must learn this language and the system is not interactive. One scripting system is ASAS (Actor Script Animation Language), which has a syntax similar to LISP. ASAS introduced the concept of an actor, i.e., a complex object which has its own animation rules. For example, in animating a bicycle, the wheels will rotate in their own coordinate system and the animator doesn't have to worry about this detail. Actors can communicate with other actors be sending messages and so can synchronize their movements. This is similar to the behavior of objects in object-oriented languages.
Procedures are used that define movement over time. These might be procedures that use the laws of physics (Physically - based modeling) or animator generated methods. An example is a motion that is the result of some other action (this is called a "secondary action"), for example throwing a ball which hits another object and causes the second object to move.
This technique allows an object to change its shape during the animation. There are three subcategories to this. The first is the animation of articulated objects, i.e., complex objects composed of connected rigid segments. The second is soft object animation used for deforming and animating the deformation of objects, e.g. skin over a body or facial muscles. The third is morphing which is the changing of one shape into another quite different shape. This can be done in two or three dimensions.
This uses stochastic processes to control groups of objects, such as in particle systems. Examples are fireworks, fire, water falls, etc.
Objects or "actors" are given rules about how they react to their environment. Examples are schools of fish or flocks of birds where each individual behaves according to a set of rules defined by the animator.
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