Weak visibility polygons of NURBS curves inside simple polygons

Visibility computation plays an important role in applications such as architectural design, art gallery patrolling and virtual worlds. In this paper, we present an algorithm to compute the weak visibility polygons (WVP) of Non Uniform Rational B-spline (NURBS) curves inside simple polygons. The NURBS curve is first subdivided into triangular curves. We then compute the WVP of each triangular curve by shearing that of its triangle hull. Finally, all triangular curves’ WVPs are merged together to obtain the WVP of the NURBS curve. Analysis and examples are given to show the performance of our algorithm.