While large investments are made in sophisticated graphics hardware, most realistic rendering is still performed off-line using ray trace or radiosity systems. A coordinated use of hardware-provided bitplanes and rendering pipelines can, however, approximate ray trace quality illumination effects in a user-interactive environment, as well as provide the tools necessary for a user to declutter such a complex scene. A variety of common ray trace and radiosity illumination effects are presented using multi-pass rendering in a pipeline architecture. We provide recursive reflections through the use of secondary viewpoints, and present a method for using a homogeneous 2-D projective image mapping to extend this method for refractive transparent surfaces. This paper then introduces the Dual Z-buffer, or DZ-buffer, an evolutionary hardware extension which, along with current framebuffer functions such as stencil planes and accumulation buffers, provides the hardware platform to render non-refr...

We investigate a new hybrid of sort-first and sort-last approach for parallel polygon rendering, using as a target platform a cluster of PCs. Unlike previous methods that statically partition the 3D model and/or the 2D image, our approach performs dynamic, viewdependent and coordinated partitioning of both the 3D model and the 2D image. Using a specific algorithm that follows this approach, we show that it performs better than previous approaches and scales better with both processor count and screen resolution. Overall, our algorithm is able to achieve interactive frame rates with efficiencies of 55.0% to 70.5% during simulations of a system with 64 PCs. While it does have potential disadvantages in client-side processing and in dynamic data management---which also stem from its dynamic, view-dependent nature---these problems are likely to diminish with technology trends in the future. Keywords: Parallel rendering, cluster computing. 1 Introduction The objective of our research is ...

This paper describes a system architecture for realtime display of shaded polygons. Performance of 100,(300 lighted, 4-sided polygons per second is achieved. Vectors and points draw at the rate of 400,000 per second. High-speed pan and zoom, alpha blending, realtime video input, and antialiased lines are supported. The architecture heavily leverages parallelism in several forms: pipeline, vector, and array processing. It is unique in providing efficient and balanced graphics that support interactive design and manipulation of solid models. After an overview of algorithms and computational requirements, we describe the details of the implementation. Finally, the unique features enabled by the architecture are highlighted.

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

A technique is described for adding natural-looking hair to standard rendering algorithms. Using an explicit hair model in which each individual hair is represented by a threedimensional curved cylinder the technique uses pixel blending combined with Z-buffer and shadow buffer information from the scene to yield a final anti-aliased image with soft shadows. Although developed for rendering human hair, this technique can also be used to render any model consisting of long filiments of sub-pixel width. The technique can be adapted to any rendering method that outputs Z-buffer and shadow buffer information and is amenable to hardware implementation.

Applications such as animation and scientific visualization demand high performance ren-dering of complex three dimensional scenes. To deliver the necessary rendering rates, highly parallel hardware architectures are required. The challenge is then to design algorithms and software which effectively use the hardware parallelism. This paper describes a rendering al-gorithm targeted to distributed memory MIMD architectures. For maximum performance, the algorithm exploits both object-level and pixel-level parallelism. The behavior of the algorithm is examined both analytically and experimentally. Its performance for large numbers of processors is found to be limited primarily by communication overheads. An experimental implementation for the Intel iPSC/860 shows increasing performance from 1 to 128 processors across a wide range of scene complexities. It is shown that minimal modifications to the algorithm will adapt it for use on shared memory architectures as well.

In this paper, we present current research developments in the Virtual Life of autonomous synthetic actors. After a brief description of the perception action principles with a few simple examples, we emphasize the concept of virtual sensors for virtual humans. In particular, we describe in details our experiences in implementing virtual vision, tactile and audition. We then describe perception-based locomotion, a multisensor based method of automatic grasping and vision-based ball games.

This paper introduces the architecture and initial algorithms for Pixel-planes 5, a heterogeneous multi-computer designed both for high-speed polygon and sphere rendering (1M Phong-shaded triangles/second) and for supporting algorithm and application research in interactive 3D graphics. Techniques are described for volume rendering at multiple frames per second, font generation directly from conic spline descriptions, and rapid calculation of radiosity form factors. The hardware consists of up to 32 math-oriented processors, up to 16 rendering units, and a conventional 1280x1024-pixel frame buffer, interconnected by a 5 gigabit ring network. Each rendering unit consists of a 128x128-pixel array of processors-with-memory with parallel quadratic expression evaluation. Implemented on fast custom CMOS chips, this array has 208 bits/pixel on-chip and is connected to a video RAM memory system that provides 4,096 bits of off-chip memory. Rendering units can be independently reassigned to any ...

Efficient visible surface determination algorithms have long been a fundamental goal of computer graphics. We discuss the well-known ray casting problem: given a geometric scene description, a synthetic camera, and a viewport which discretizes the camera film plane into pixels, ray casting identifies the visible surface at each pixel, i.e., that scene primitive which is first encountered by an eye ray directed through the pixel center. Interactive rendering systems...

In a recent alternative research path for interactive 3D graphics the scene to be rendered is described with images. Image-based rendering (IBR) is appealing since natural scenes, which are very difficult to model conventionally, can be acquired semi-automatically using cameras and other devices. Also IBR has the potential to create high-quality output images if the rendering stage can preserve the quality of the reference images (photographs). One promising IBR approach enhances the images with perpixel depth. This allows reprojecting or warping the color-and-depth samples from the reference image to the desired image. Image-based rendering by warping (IBRW) is the focus of this dissertation. In IBRW, simply warping the samples does not suffice for high-quality results because one must reconstruct the final image from the warped samp...