#
Smooth Interpolation of Orientations with Angular Velocity Constraints using Quaternions

Alan H. Barr, Bena Currin--California Institute of Technology

Steven Gabriel--Sage Design

John F. Hughes--Brown University

From *Proceedings of SIGGRAPH 1992*, ACM SIGGRAPH, 1992, p.
313-320. Abstract is
available

## Abstract

In this paper we present methods to smoothly interpolate orientations, given N
rotational keyframes of an object along a trajectory. The methods allow the
user to impose constraints on the rotational path, such as the angular
velocity at the endpoints of the trajectory.
We convert the rotations to quaternions, and then spline in that non-Euclidean
space. Analogous to the mathematical foundations of flat-space spline curves,
we minimize the net "tangential acceleration" of the quaternion path. We
replace the flat-space quantities with curved-space quantities, and
numerically solve the resulting equation with finite difference and
optimization methods.