User:Jl2068/sandbox

Behavior Authoring for Character Animation

Introduction
In contrast to the cinema, which is a linear medium as for any given film the audience’s journey is always the same, current computer games are non-linear, offering variation and interactivity. Because it is possible to create characters for these games that convey a sense of psychological engagement. There are many tools and algorithms for authoring behavior of virtual animation. Most of their motivation is to create believable characters in real-time with user defined rules or description (e.g. scripts) which is easy to use. These utilities and approaches can be applied to different aspects of a virtual characters: some of them focus on interactive characters, some focus on emotions, some focus on multi-character animations, etc.

Improv
One of the first authoring systems for interactive character applications is Improv. Improv builds believable characters that respond to users and to each other in real-time, with consistent personalities, properly changing moods and without mechanical repetition, while always maintaining an author’s goals and intentions. The system has been implemented using an ”english-style” scripting language and a network distribution model to enable creative experts, who are not primarily programmers, to create powerful interactive applications.

Visual SceneMaker
SceneMaker’s central authoring paradigm is the separation of content (e.g. dialogue) and logic (e.g. conditional branching). The content is organized as a collection of scenes which are specified in a multi-modal scenescript resembling a movie script with dialogue utterances and stage directions for controlling gestures, postures, and facial expressions. The logic of an interactive performance and the interaction with virtual characters is controlled by a sceneflow. A sceneflow is a hierarchical state chart variant specifying the logic and temporal order in which individual scenes are played, commands are executed and user interactions are processed. An IDE, the Visual SceneMaker IDE, is also included in the system. This IDE enables authors to create, maintain, debug, and execute an application via graphical interface controls.

BAAP
BAAP, a behavioral animation authoring platform for emotion driven 3D virtual characters, following the model proposed in, focuses on emotion modeling and behavior organizing. In BAAP, the behavior DAG, is implemented. There are four kinds of organizations for executing behaviors: Sequence (All the direct children should execute in turn), Selector (At most one direct child is chosen to execute), Repeat (All the direct children should execute in turn for several times) and Parallel (All the direct children should start execution at the same time).

The BML Sequencer
The BML Sequencer is a tool for authoring multi-character animations. This system uses the BML (Behavior Markup Language), an XML based language, to control virtual characters’ non-verbal behaviors. The BML sequencer tool has a simple user interface allowing artists to rapidly realize their vision for expressive multi-character behavior. Three animation channels are provided: Body Animations, Facial Animations, and Gazes.