Apple Computer, Inc. Traditional radiosity methods can compute the illumination for a scene independent of the view position. However, if any part of the scene geometry is changed, the radiosity process will need to be repeated from scratch. Since the radiosity

We describe a system that computes radiosity solutions for polygonal environments much larger than can be stored in main memory. The solution is stored in and retrieved from a database as the computation proceeds. Our system is based on two ideas: the use of visibility oracles to find source and blocker surfaces potentially visible to a receiving surface; and the use of hierarchical techniques to represent interactions between large surfaces efficiently, and to represent the computed radiosity solution compactly. Visibility information allows the environment to be partitioned into subsets, each containing all the information necessary to transfer light to a cluster of receiving polygons. Since the largest subset needed for any particular cluster is much smaller than the total size of the environment, these subset computations can be performed in much less memory than can classical or hierarchical radiosity. The computation is then ordered for further efficiency. Careful ordering of ene...

Radiosity is a widely used technique for global illumination. Typically the computation is performed offline and the result is viewed interactively. We present a technique for computing radiosity, including an adaptive subdivision of the model, using graphics hardware. Since our goal is to run at interactive rates, we exploit the computational power and programmability of modern graphics hardware. Using our system on current hardware, we have been able to compute and display a radiosity solution for a 10,000 element scene in less than one second. Key words: Graphics Hardware, Global Illumination. 1

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...

This paper deals with the rendering issues of the problem of producing a real-time convincing surgery simulation. The main scope of our project is to simulate laparoscopic liver surgery. Nevertheless large parts of the technique apply to other organs. We address three aspects of the appearance of the organ surface: the organ skin texture, the specular highlights, and the reactions of the organ to the instruments.

In this paper, we present a modified version of the virtual wall concept we introduced in a previously published paper. The goal of our work is to design a strategy to handle very complex scenes (more than 1 million of patches) for radiosity computation. Comparing to other radiosity algorithms, our solution focuses on the ability to compute the radiosity on local environments instead of solving the problem for the whole environment. By splitting the problem into subproblems, using Virtual Interface and Visibility Masks, our technique is able to achieve better data locality than other standard solutions. This property is capital when using either a modern sequential computer to reduce data movement in the memory hierarchy or a multiprocessors to keep as low as possible communication between processors whatever the communication paradigm is: either message passing or shared variable. In the paper, we present an implementation of visibility masks on a distributed memory parallel computer ...

We present a data parallel algorithm for radiosity. The algorithm was designed to take advantage of large numbers of processors. It has been implemented on the Connection Machine CM2 system and scales linearly in the number of available processors over a wide range. All parts of the algorithm -- form-factor computation, visibility determination, adaptive subdivision, and linear algebra solution -- execute in parallel with a completely distributed database. Load balancing is achieved through processor allocation and dynamic data structures which reconfigure appropriately to match the granularity of the required calculations.

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...

This paper presents the state-of-the-art parallel rendering techniques for interpolation shading, raytracing and radiosity. In addition the most sophisticated parallel architectures for real time rendering are introduced. The new Virtual Walls concept especially designed for asyncronously distributed multiprocessor systems is presented by the author. It describes new distributed rendering techniques based on spatial subdivision and has already been implemented on massively parallel transputer systems and on networks of workstations. Keywords: Parallel, Rendering, Raytracing, Radiosity. 1 Introduction Parallel rendering techniques is a field whose time has come. Until recently for the most it was an cumbersome specialty involving complicated and expensive hardware. In addition the programmers of distributed software had to begin to think parallel. In the last few years, however, there has been a steady and sometimes even spectacular reduction in the hardware price/performance ratio an...