Categories and Subject Descriptors F.2.2 [Analysis of Algorithms and Problem Complexity]: Nonnumerical Algorithms and Problems—geometrical problems and computations General Terms Algorithms, Theory

In a landmark survey of visibility algorithms in 1974, Sutherland, Sproull, and Schumacker stated that “We believe the principal untapped source of help for hidden surface algorithms lies in frame and object coherence. ” [11] Making use of such temporal coherence appears to be difficult, however, for scenes with moving objects. Almost three decades later Cohen-Or, Chrysanthou, and Silva stated that “The efficient handing of dynamic scenes is an open area of research at this point. ” [3] This five minute video describes a kinetic visibility algorithm for moving objects in the plane that is provably efficient in an average case setting. The corner arc algorithm is a Kinetic Data Structure [2] which makes use of new properties of pseudo-triangulations [9]. The corner arc algorithm and its analysis are given in Chapters 4 and 5 of a thesis on kinetic visibility algorithms [6] where the proofs and more detail for the theorems in this abstract are found. 1. SETTING Four difficulties arise in designing an appropriate setting for analyzing the computational complexity of maintaining visibility among moving objects. First, the efficiency of a visibility algorithm typically depends on the number of objects visible to the observer, and this number may vary greatly as the objects move. Second, object motion may result in collisions between objects, and changes to object trajectories due to collisions may easily result in complex Copyright is held by the author/owner