In computer graphics, rendering is the process by which an abstract description of a scene is converted to an image. When the scene is complex, or when high-quality images or high frame rates are required, the rendering process becomes computationally demanding. To provide the necessary levels of performance, parallel computing techniques must be brought to bear. Although parallelism has been exploited in computer graphics since the early days of the field, its initial use was primarily in specialized applications. The VLSI revolution of the late 1970Õs and the advent of scalable parallel computers during the late 1980Õs changed this situation. Today, parallel hardware is routinely used in graphics workstations, and numerous software-based rendering systems have been developed for general-purpose parallel architectures. This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering

This paper describes algorithms that allow multiple hierarchical radiosity solvers to work on the same radiosity solution in parallel. We have developed a system based on a group iterative approach that repeatedly: 1) partitions patches into groups, 2) distributes a copy of each group to a slave processor which updates radiosities for all patches in that group, and 3) merges the updates back into a master solution. The primary advantage of this approach is that separate instantiations of a hierarchical radiosity solver can gather radiosity to patches in separate groups in parallel with very little contention or communication overhead. This feature, along with automatic partitioning and dynamic load balancing algorithms, enables our implemented system to achieve significant speedups running on moderate numbers of workstations connected by a local area network. This system has been used to compute the radiosity solution for a very large model representing a five floor building with furni...

Global illumination is an area of research which tries to develop algorithms and methods to render images of

The radiosity method models the interaction of light between diffuse surfaces, thereby accurately predicting global illumination effects. Due to the high computational effort to calculate the transfer of light between surfaces and the memory requirements for the scene description, a distributed, parallelized version of the algorithm is needed for scenes consisting of thousands of surfaces. We present

This paper presents a multi-computer, parallel version of the recently-proposed "Density Estimation" (DE) global illumination method, designed for computing solutions of environments with high geometric complexity (as many as hundreds of thousands of initial surfaces). In addition to the diffuse inter-reflections commonly handled by conventional radiosity methods, this new method can also handle energy transport involving arbitrary non-diffuse surfaces. Output can either be Gouraud-shaded elements for interactive walkthroughs, or ray-traced images for higher quality still frames. The key difference of the DE algorithm from conventional radiosity, in terms of its ability to parallelize efficiently, is its microscopic view of energy transport, which avoids the O(n 2 ) pairwise surface interactions of most previous macroscopic radiosity algorithms (i:e:, those without clustering). Parallel DE is implemented as two separate parallel programs which perform different phases of the DE metho...

The radiosity method is a very demanding process in terms of computing and memory resources. To cope with these problems, parallel solutions have been proposed in the literature. These solutions are outlined and classified in this paper. A new parallel solution, based on the use of a shared virtual memory (SVM), is proposed. It will be shown that this concept of SVM greatly simplifies the implementation of a parallel algorithm. This new parallel radiosity algorithm has been implemented on an iPSC/2 hypercube using KOAN SVM. The first results obtained with this algorithm are encouraging since the calculated efficiency curve is nearly linear. keywords: Rendering algorithm, Radiosity, Parallelism, Shared Virtual Memory, Distributed Memory parallel Computers. 1 Introduction Radiosity is getting more and more popular since it is able to simulate one of the most important form of illumination, the indirect ambiant illumination provided by light reflected among the many diffuse surf...

The quality of synthetic images depends, first, on the quality of the modelling of the three-dimensional scenes to visualize; more numerous are the geometrical and optical details, more realistic are the resulting images. Unfortunately, such scene descriptions need a big amount of memory, as well as a long time of computation. In order to deal with these restrictions, we propose a parallel implementation for an extended stochastic progressive radiosity method, where form factors are computed with a ray tracing scheme, on a network of processors with a distributed memory and a message passing mechanism. Our program has already treated very big scenes (more than one million patches for example). Keywords: Image Synthesis, Realistic Rendering, Progressive Radiosity, Parallelism, MIMD, Multi-Threading. 1 Introduction Image synthesis is decomposed in two parts. First, the modelling step describes the geometrical and optical properties of the scene to be rendered. By geometrical descriptio...

The progressive refinement method is investigated for parallelization on ring-connected multicomputers. A synchronous scheme, based on static task assignment, is proposed, in order to achieve better coherence during the parallel light distribution computations. An efficient global circulation scheme is proposed for the parallel light distribution computations, which reduces the total volume of concurrent communication by an asymptotical factor. The proposed parallel algorithm is implemented on a ring-embedded Intel's iPSC/2 hypercube multicomputer. Load balance quality of the proposed static assignment schemes are evaluated experimentally. The effect of coherence in the parallel light distribution computations on the shooting patch selection sequence is also investigated. Keywords : Progressive refinement radiosity, parallel computing, multicomputers, ring interconnection topology. 1 Introduction Radiosity [7] is an increasingly popular method for generating realistic images of nonex...

The radiosity method models the interaction of light between diffuse reflecting surfaces, thereby accurately predicting global illumination effects. Due to the high computational effort to calculate the transfer of light between surfaces and the memory requirements for the scene description, a distributed, parallelized verison of the algorithm is needed for scenes consisting of thousands of surfaces. We present a distributed, parallel radiosity algorithm, which can subdivide the surfaces adaptively. Additionally we present a scheme for parallel visibility calculations. Adaptive load redistribution is also discussed.

: The quality of synthetic images depends, first, on the quality of the modeling of the three-dimensional scene to visualize. More numerous are the specified geometrical and optical details, more realistic is the result image. Unfortunately, such scene descriptions need a big amount of memory, and then they need a long time of computation. In order to deal with these restrictions, we propose a parallel implementation for an extended stochastic progressive radiosity method, where form factors are computed with a ray tracing scheme, on a network of processors with a distributed memory and a message passing mechanism. Our program is able to treat very big scenes (more than one million patches for example). Keywords : Image Synthesis, Realistic Rendering, Progressive Radiosity, Parallelism, MIMD, MultiThreading 1 Introduction Image synthesis is decomposed in two parts. First, the modeling step describes the geometrical and optical properties of the scene to be rendered. By geometrical d...