ScrewBender: Smoothing Piecewise Helical Motions

An ordered series of control poses may be interpolated by a polyscrew (piecewise helical) rigid body motion composed of a series of screws, each interpolating a pair of consecutive control poses. The trajectory of each point during a screw motion segment is C. Although a polyscrew is continuous, velocities are typically discontinuous at control poses when the motion switches between screws. We obtain a smooth motion by subdividing the polyscrew. Three subdivision schemes are proposed: the interpolating 4-point subdivision, the smooth cubic B-spline subdivision, and the new Jarek subdivision, an average of these two. Their implementation is trivial and their computation sufficiently fast for realtime subdivision and animation, which is particularly important for interactive motion editing.

• Type: Journal
• Year: 2008
• Where: CGA
• Authors: Alexander Powell, Jarek Rossignac
• Keywords: CGA 2008, Computational Geometry, Cubic B-spline Subdivision, Screw Motion Segment, Screws