Eva Schiffer

Real Time Responsive Animation with Personality
by Ken Perlin, IEEE TVCG (Trans on Visualization and Comp Graphics), 1995 (Vol 1, Issue 1)

Summary:

This paper describes a system through which a set of basic motions can be defined and a simple system of transitions can be created based on various simple kinematic assumptions. At run time a puppet can be driven by these basic motions and some user input which controls when and where blends are made.

Problem:

The author is trying to tackle the problem of how to create a powerful and flexible system of motions to allow a user to direct a puppet at a higher level and still receive a believable performance. 

Method:

The basic method used here is to programatically define a set of motions that the puppet can use, define a set of blends between the motions, define a set of constraints on the motions (and indirectly the blends), and define some basic kinematic assumptions. Using all of this, the puppet can use random noise functions as well as some user defined constraints to move around in the environment. 

Key Ideas:

Motions can be designed to form a system of movement for a 3D puppet that is complete and expressive.
Blends can be designed so as to preserve constraints and thus realism of the blended motions.
Further constraints can be used to model high level behavior such as what the puppet is paying attention to. 

Contributions:

This paper presents a programmatic way of defining rhythmic motion simply as well as powerful non-linear system of forming smooth blends and time warping using motion tempo. 

Questions:

I would like to know how much of the input for the puppet was defined by the animator/programmer before hand and how much, if any, came from the user at run time.