symSpline

We introduce symSpline: a symmetric, dual-mouse technique for the manipulation of spline curves. In symSpline, two cursors control the positions of the ends of the tangent to an edit point. By moving the tangent with both mice, the tangent and the edit point can be translated while the curvature of the spline is adjusted simultaneously, according to the length and angle of the tangent. We compare the symSpline technique to two asymmetric dual-mouse spline manipulation techniques and to a standard single-mouse technique. In a spline matching experiment, symSpline outperformed the two asymmetric dual-mouse techniques and all three dual-mouse techniques proved to be faster than the single-mouse technique. Additionally, symSpline was the technique most preferred by test participants.