In 1992, Barr et al. proposed a method for interpolating orientations with unit quaternion curves by minimizing covariant acceleration. This paper presents a simple improved method which uses cubic basis functions to achieve a speedup of up to three orders of magnitude. A new criterion for automatic refinement based on the Euler-Lagrange error functional is also introduced. CR Categories: I.3.5 [Computer Graphics]: Computational
Ravi Ramamoorthi, Alan H. Barr