Issue No. 09 - September (1984 vol. 4)
Herbert Steinberg , MAGI, Mathematical Applications Group, Inc.
Ray tracing can generate high-quality color images of free-form surfaces. To reduce CPU time, introduce extra knots into the system and use biquadratics instead of bicubics.
H. Steinberg, "A Smooth Surface Based on Biquadratic Patches," in IEEE Computer Graphics and Applications, vol. 4, no. , pp. 20-23, 1984.