### Summary

Motion graphs provide a nice framework from which a large database of motion data can be used to create new, arbitrarily long clips of motion. Generating motion for interactive applications has certain requirements that are not necessarily met by motion graphs, however. Interactive applications demand that the avatar be both highly controllable and responsive to human input. Currently this requires a great deal of work by hand in order to capture the desired motions exactly and create the necessary transitions. It would be desirable to leverage current databases of motion capture data along with automatic transition generation in order to make this process much less time consuming.

To do this, the paper proposes imposing a specific structure on motion graphs. First, motion graphs with high connectivity provide a the user with a large amount of control over what action to perform next. Second, having these motions leave and enter a common hub node allows the system to be even more controllable -- it permits a much larger array of motions to be played after a given motion. Third, short motion clips allow the system to be responsive as an arbitrarily chosen clip selected by the user can play much sooner if the current clip is short.

### Problem

Avatars in interactive applications such as games must be both controllable and responsive. Motion graphs provide a way for leveraging a large motion database to connect clips of motion in to new motions. However, there is no guarentee as to the structure of the graph. Reaching a certain clip of motion may require playing a long clip of motion or traversing several nodes to reach the desired motion.

### Solution

Impose a desirable structure on a motion graph in order to make it useful for interactive applications. Specifically, they require that the graph have very high connectivity via a small number of "hub" nodes. This is done by identifying very similar frames and constructing from them a "common pose." Displacement maps are generated to transform motion clips to/from the common pose at the beginning and end of the clips. By having a large number of short motion clips all passing through a common node, the desired structure is achieved.

### Contributions

1. Method for imposing a certain structure on motion graphs favoring high connectivity and a small amount of hub nodes.

2. Software for the authoring of such a graph.

### Questions, Comments, Flaws

This idea is simple yet powerful. It allows a large motion database to be used to create a structure useful in interactive applications that would otherwise require a large investment of time by a talented animator.