  This paper extends previous research in that sense that for orthogonal
projections of rigid smooth (true-3D) curves moving totally free it reduces the
number of required traceable points to two only (the best results known so far
to the author are 3 points from free motion and 2 for motion restricted to
rotation around a fixed direction and and 2 for motion restricted to influence
of a homogeneous force field). The method used is exploitation of information
on tangential projections. It discusses also possibility of simplification of
reconstruction of flat curves moving free for prospective projections.
