Abstract
The purpose of this paper is to find the quantities and surfaces of a line congruence via
examining it in the dual space and to represent the results more appropriately for computational
approximations. For this, we take mainly two-dual parameter motion on the dual unit sphere (DUS)
so, we get a line congruence corresponding this motion by a new method. Thus, the equations of
the developable surfaces, the principal surfaces, the focal surfaces and the center surface of the line
congruence are found by coordinate functions. The results are illustrated by examples.