A comparison of three dimensional maximum reach estimation techniques.

Spiine, periodic spline and spherical harmonic maximum reach estimation procedures are compared and evaluated based on ease of usage, estimation error and bias. The comparison indicates that each method provides comparable estimates based on percent variance accounted for (Rz) and standard error. Spherical harmonics, however, are less biased and provide accurate estimates of the maximum reach sphere at the north and south poles, whereas splines and periodic splines are substantially biased in &se regions. Three dimensional computer graphic depictions of reach data for the seati operator illustrate these biases.