We consider the distributed setting of $N$ autonomous mobile robots that operate in <i>Look-Compute-Move</i> cycles following the well-celebrated <i>classic oblivious robots</i> model. We study the fundamental problem where starting from an arbitrary initial configuration, <i>N</i> autonomous robots reposition themselves to a convex hull formation on the plane where each robot is visible to all others (the Complete Visibility problem). We assume obstructed visibility, where a robot cannot see another robot if a third robot is positioned between them on the straight line connecting them. We provide the first \cO(N) time algorithm for this problem in the fully synchronous setting. Our contribution is a significant improvement over the runtime of the only previously known algorithm for this problem which has a lower bound of \Omega(N^2). Our proposed algorithm is collision-free -- robots do not share positions and their paths do not cross.