Data-Parallel Volume Rendering Algorithms

Abstract

this paper we consider a general scheme for parallel volume rendering, presented in Section 1.1. We describe an algorithm that has an extremely efficient implementation on distributed memory MIMD architectures and is suitable for hardware implementation based on the image composition architectures [9]. This data parallel scheme assigns a portion of the volume to each processor which renders it with any one of the above mentioned rendering algorithms. The resulting images from all processors are then combined (composited) in visibility order to form the final image. As viewing and shading parameters change, 3D voxel data is not communicated between processors. Communication involves only 2D partial images. In Section 3 we report on two specific rendering algorithms that can be executed in each processor to generate the image of the local sub-volume. These algorithms take advantage of vector processing or pipelining capabilities available on some parallel machines (Intel Paragon, IBM Power Visualization System (PVS)). Section 4 contains performance analysis and provides results of experiments examining various aspects of the proposed algorithm and its variations. Although experiments were conducted on particular machine (IBM PVS), the results reported here are relevant to all parallel machines which belong to the MIMD class of architecture. Also, even if individual processors of the parallel machine do not support vector operations, the performance trends exhibited by the algorithm would still hold. The algorithms are also very suitable for hardware implementation based on image composition architecture. Finally, Section 5 contains concluding remarks and future plans. 4 2. Volume Rendering by Parallel Image Compositio