Recently, we proposed a new isosurface extraction algorithm that extracts portions of the isosurface in a viewdependent manner by ray casting and propagation. The algorithm casts rays through a volume to find visible active cells as seeds and then propagates their polygonal isosurface into the neighboring cells. Small pieces of the isosurface are generated by distance-limited propagation and joined together to form the final surface. This paper presents our evaluation of several design choices of the algorithm. We have implemented these design choices and showed that by making right design decisions, we can substantially reduce the time to obtain most (such as 99.9%) of the isosurface. r 2002 Elsevier Science Ltd. All rights reserved.