Cosenza, BiagioCordasco, GennaroChiara, Rosario DeErra, UgoScarano, VittorioVittorio Scarano and Rosario De Chiara and Ugo Erra2014-01-272014-01-272008978-3-905673-68-5https://doi.org/10.2312/LocalChapterEvents/ItalChap/ItalianChapConf2008/097-104In this paper we estimate the effectiveness of exploiting coherence in Parallel Ray Tracing. We present a load- balancing technique which divides the original rendering problem in balanced subtasks and distribute them to independent processors through a Prediction Binary Tree (PBT). Furthermore the PBT allows to exploit temporal coherence among successive image frames. At each new frame, it updates the current PBT using a cost function which uses the previous rendering time as cost estimate. We also provide two heuristics which take advantage of data-locality. We assess the effectiveness of the proposed solution by running two experiments. The £rst one aims to investigate the accurancy of predictions made using the PBT. Results show that such predictions are quite accurate even considering a heavily unbalanced scene and a fast moving camera. The second experiment evaluates the two locality-aware heuristics showing a modest improvement.Categories and Subject Descriptors (according to ACM CCS): C.1.4 [Processor Architectures]: Parallel Architectures I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism.