Envelopes of moving quadric surfaces
The authors compute the characteristics of the envelope of a family of quadrics (also degenerate) generated by a fixed quadric dragged along a space curve and rigidly connected to the Frenet frame of the curve. \{The Frenet frame is nor very convenient in Computer Graphics; for better choice of the frame cf. \textit{F. Klok}, ibid. 3, 217-229 (1986; Zbl 0631.65145); the reviewer, ibid. 6, 77-78 (1989; Zbl 0664.65017)\}.
scientific article; zbMATH DE number 97034