Conoid

A conoid (from Greek κωνος cones and ειδης similar) is a ruled surface, that is, it is formed by straight generatrix. More control surfaces are cylinders, cones, hyperbolic paraboloids and Rotationshyperboloide. Straight lines which are parallel to a reference plane and cut a directrix and a spine form a conoid. The term has been marked by Archimedes in his treatise On Conoids and spheroids.

• Space geometry