VISUALIZING ORIENTATION USING QUATERNIONS

Abstract

INTRODUCTION: Visualization of 3D kinematic data presents special challenges, not only in terms of hardware requirements, but also in terms of the mathematics used to describe it. The ISB Standardization and Technology Committee has been working to standardize methods for representing kinematic data, particularly in the definition of coordinate systems and the representation of spatial orientations. In this presentation we will show that, although the ISB’s recommendation to regard a segment’s orientation as an ordered series of rotations may be useful for reporting and comparing results, it is not particularly suitable for 3D animation. The fundamental problems in ordered series of rotations will be briefly summarized. We will contrast this with the algebraic elegance of the quaternion and its usefulness as a rotation operator. The advantages of quaternions will be visually demonstrated by showing them “in action” in examples of real-time key frame animations.