A reformulated radiosity algorithm is presented that produces initial images in time linear to the number of patches. The enormous memory costs of the radiosity algorithm are also elim-inated by computing form-factors on-the-fly. The technique is based on the approach of rendering by progressive refinement. The algorithm provides a useful solution almost immediately which progresses gracefully and continuously to the complete radiosity solution. In this way the competing demands of real-ism and interactivity are accommodated. The technique brings the use of radiosity for interactive rendering within reach and has implications for the use and development of current and future graphics workstations.

This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy (photons) from the light sources and storing these as they hit surfaces within the scene. We use one high resolution caustics photon map to render caustics that are visualized directly and one low resolution photon map that is used during the rendering step. The scene is rendered using a distribution ray tracing algorithm optimized by using the information in the photon maps. Shadow photons are used to render shadows more efficiently and the directional information in the photon map is used to generate optimized sampling directions and to limit the recursion in the distribution ray tracer by providing an estimate of the radiance on all surfaces with the exception of specular...

A new progressive global illumination method is presented which produces approximate images quickly, and then continues to systematically produce more accurate images. The method combines the existing methods of progressive refinement radiosity, Monte Carlo path tracing and light ray tracing. The method does not place any limitation on surface properties such as ideal Lambertian or mirror-like. To increase efficiency and accuracy, the new concepts of light source reclassification, caustics reconstruction, Monte Carlo path tracing with a radiosity preprocess and an interruptible radiosity solution are introduced. The method presents the user with most useful information about the scene as early as possible by reorganizing the method into a radiosity pass, a high frequency refinement pass and a low frequency refinement pass. The implementation of the method is demonstrated, and sample images are presented.

In this paper we present a new Monte Carlo rendering algorithm that seamlessly integrates the ideas of

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

This thesis presents a volumetric representation for the global illumination within a space based on the radiometric quantity irradiance. We call this representation the irradiance volume. Although irradiance is traditionally computed only for surfaces, its de nition can be naturally extended to all points and directions in space. The irradiance volume supports the reconstruction of believable approximations to the illumination in situations that overwhelm traditional global illumination algorithms. Atheoretical basis for the irradiance volume is discussed and the methods and issues involved with building the volume are described. The irradiance volume method is tested within several situations in which the use of traditional global illumination methods is impractical, and is shown to provide good performance.

Realistic image generation is presented in a theoretical formulation that builds from previous work on the rendering equation. Previous and new solution techniques for the global illumination are discussed in the context of this formulation. The basic

Several ways of improving the realism of the results of traditional ray tracing are presented. The essential physical quantities of spectral radiant power and spectral radiance and their use in lighting calculations are discussed. Global illumination terms are derived by employing illumination ray tracing for calculation of quickly changing indirect lighting components, and radiosity ray tracing for slowly changing indirect lighting components. Direct lighting is calculated during the viewing phase allowing the use of bump maps. Finally, a method is introduced that reduces the total number of shadow rays to no more than the total number of viewing rays for a given picture. Keywords: Bump Mapping, Illumination, Radiosity, Radiance, Ray Tracing, Realism, Stratified Sampling, Texture Mapping. 1 Introduction The quest for accurate lighting models in computer graphics has taken two very different approaches in the 1980s. The first approach is based on ray tracing (point sampling) techniqu...

A coordinated use of hardwareprovided bltplanes and rendering pipelines can create fast ray traced quality illumination effects for dynamic environments by using Multi-pass Pipeline Rendering (MPR) techniques. We provide recttrsive reflections and refractions through the use of secondary viewpoints and projective image mapping. We extend the traditional use of shadow volumes to provide global direct illumination effects which fit into our recursive viewpoint paradiim. Hardware surface shading is fit to a physicallybaaed BRDF to provide a better local model, and the framework permits incorporation of indirect illumination as well. Furthermore, material transmittance is approximated using an extension to projective textures. Together, these techniques provide a platform for producing realistic images in highly dynamic environments. While most appropriate for scenes which specular components contribute largely to the secondary illumination, the integration of MPR with indirect racliosity solutions also provides a dynamic solution for highly diffuse environments. These techniques are immediately applicable to areas such as walkthroughs, animation, and interactive dynamic environments to produce more realistic images in near real-time.

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...