ACHSENRICHTUNGSBESTIMMUNG EINES HYPERBOLISCHEN PARABOLOIDS

Determination of the axis direction of a hyperbolic paraboidWhen the direction planes of both generatrix sets of the hyperbolic paraboloid are projection planes then their intersection, the direction of the axis, appears as a point. In this case the distorted surface quadrangle created by any two primary generatrices and any two secondary ones seems a parallelogram where the halving points of the diagonals coincide. This means only covering for a distorted quadrangle. Thus linking the halvingpoints of the two diagonals of an arbitrary distorted quadrangle in any projection yields the direction of the axis of the hyperbolic paraboloid.