ELSEVIER Parallel Computing 23 (1997) 943-952 zyxwvutsrqponmlkjihgfedcbaZYXWVUTS PARALLEL COMPUTING Profiling for efficient parallel volume visualisation Cemal K&e * .l, Alan Chalmers zyxwvutsrqponmlkjihgfedcbaZYX Depurtment zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA of Computer Science, Uniuersity zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ of Bristol, Bri.stol, BS8 I UB, UK Received 1 June 1996; revised 21 November 1996 Abstract Visualising a multi-dimensional volume data set is a computationally intensive process. Parallel processing offers the potential for achieving the visualisation in a reasonable time. This paper discusses how an appropriate data management approach and the correct management of tasks in the parallel implementation can improve overall system performance. A number of profiling and load balancing strategies are considered to exploit any coherence that may exist as the view point moves. Keywords: Volume visualisation; Prefetching; Load balancing; Profiling 1. Introduction Volume visualisation allows meaningful and intuitive information to be extracted from three-dimensional volume data. Volume data sets, such as medical data from CAT or MRI scans, are becoming more freely available. The ability to interactively visualise these provides a powerful tool to scientists and engineers, allowing them to examine a complex three dimensional volume from a variety of orientations and to investigate its structure and complexity 131. The volume is visualised by rendering it from selected view points. The rendering of the volume is achieved by converting the volume data into a two dimensional image. In the simplest form a volume is defined as a collection of voxels, or small cubic cells. Each voxel stores a collection of attributes pertaining to a unit of space. These attributes may consist of, for example, a scalar value representing material density or a vector representing flow direction. Each voxel thus has visual properties such as colour, opacity * Corresponding author. E-mail: alan.chalmers@bristoI.ac.uh ’ Supported by the Black Sea Technical University. Turkey. 0167~8191/97/$17.00 Copyright 0 1997 Elsevier Science B.V. All rights reserved P/I SO167-Sl9l(97)00036-7