"Using Mocap Envelopes to Reach Target Points"

Supervised by A.Watt

Abstract

This work examines the ways in which motion capture (mocap) sequences can be mixed together, and produces an interactive game where the figure attempts to catch a ball.

A program is produced which plays back mocap sequences, allowing the operator to vary parameters and mix two sequences together in real time. From this an analysis is made of the data types which can be used for the storage and interpolation of the motion data. Euler angles, transformation matrices, axis/angle pairs and quaternions are used, and their respective advantages and disadvantages are examined. This part of the work concludes with a recipe of issues which need to be addressed before choosing the sequences.

Key points in the figure`s motion (in this case a trace of the movement of the right hand) are stored for each of the mixes as a set of envelope data, which therefore describes all possible positions of that point in the range of mocap mixes. This data is calculated at the start of the interactive game program. In the game the user can vary the mix percentages, thus moving between the two sequence motions, in order to find a point where the right hand will coincide with the spatial position of the ball – the target point.

This simple game is then tested by a number of players, and evaluated in terms of its realistic interpretation of motion and sense of the catching of the ball.