Hidden-line algorithms published before 1984 [REF] [REF] [REF] [REF] divide edges into line segments by the intersection points of their images, and then test each segment for visibility against each face of the model.
Ottmann and Widmayer [REF] and Ottmann, Widmayer and Wood [REF] proposed O((n + k)log2 n) time hidden-line algorithms.