Xavier Pueyo

A survey on participating media rendering techniques

Rendering participating media is important for a number of domains, ranging from commercial applications (entertainment, virtual reality) to simulation systems (driving, flying, and space simulators) and safety analyses (driving conditions, sign visibility). This article surveys global illumination algorithms for environments including participating media. It reviews both appearance-based and physically-based media methods, including the single-scattering and the more general multiple-scattering techniques. The objective of the survey is the characterization of all these methods: identification of their base techniques, assumptions, limitations, and range of utilization. It concludes with some reflections about the suitability of the methods depending on the specific application involved, and possible future research lines.

A Survey of Inverse Rendering Problems

Inverse rendering problems usually represent extremely complex and costly processes, but their importance in many research areas is well known. In particular, they are of extreme importance in lighting engineering, where potentially costly mistakes usually make it unfeasible to test design decisions on a model. In this survey we present the main ideas behind these kinds of problems, characterize them, and summarize work developed in the area, revealing problems that remain unsolved and possible areas of further research.

Global Illumination Techniques for the Simulation of Participating Media

This paper surveys global illumination algorithms for environments including participating media and accounting for multiple scattering. The objective of this survey is the characterization of those methods: Identification of their base techniques, their assumptions, limitations and range of utilization. To this end, the algorithms are grouped into functional categories and each method is briefly reviewed, with a discussion of its complexity and its pros and cons. We finish by discussing some applications as well as remaining areas for investigation.

Global multipath Monte Carlo algorithms for radiosity

We present a new algorithm for radiosity, which is linear both in time and storage with the number of patches in a given scene; that is, the number of patches is increased by dividing each existing patch into smaller patches. The new algorithm is based on Integral Geometry and on the well-known algorithms for Monte Carlo particle transport. It considers the scene embedded in a field of lines, each representing the exchange between the pairs of points that result from the intersections of the line with the scene. For a given pair of points, this exchange is bidirectional. Lines are taken randomly. Both graphical and numerical results are given for the proposed algorithm, which is compared with a local Monte Carlo particle transport algorithm.

The Stochastic Ray Method for Radiosity

This paper solves the system of radiosity equations with a stochastic numerical approach. Due to the high complexity of the problem for highly complex scenes, a stochastic variation of Jacobi iteration is developed which converges stochastically to the correct solution. The new method, called the Stochastic Ray Method, is a significant improvement of Stochastic Radiosity. A large number of independent rays is chosen stochastically by importance sampling of the patches according to their power after the previous iteration step. They all carry an equal amount of power into random directions, thereby representing together the total energy interreflection of the entire environment in a stochastic manner. Assuming a correctly distributed initial solution, which can be reached easily, the iteration process converges quickly and reduces the error in the result faster than other stochastic radiosity approaches. The new algorithm can easily be extended to treat various phenomena which are normally rather costly to incorporate in radiosity environments, perfect specular reflection and specular transmittance, non-diffuse self-emission and point light sources.

Rendering Techniques ’96

The Light Volume: An Aid to Rendering Complex Environments.- Light-Driven Global Illumination with a Wavelet Representation of Light Transport.- Global Illumination using Photon Maps.- Geometry Caching for Ray-Tracing Displacement Maps.- Cost Prediction in Ray Tracing.- Towards an Open Rendering Kernel for Image Synthesis.- Fast Rendering of Subdivision Surfaces.- High-Fidelity Radiosity Rendering at Interactive Rates.- Non-symmetric Scattering in Light Transport Algorithms.- Rendering Participating Media with Bidirectional Path Tracing.- Quasi-Monte Carlo Radiosity.- Importance-Driven Stochastic Ray Radiosity.- Efficiently Representing the Radiosity Kernel through Learning.- Accurate Error Bounds for Multi-Resolution Visibility.- Proximity Radiosity: Exploiting Coherence to Accelerate Form Factor Computations.- Error Control for Radiosity.- Hierarchical Rendering of Trees from Precomputed Multi-Layer Z-Buffers.- A Temporal Image-Based Approach to Motion Reconstruction for Globally Illuminated Animated Environments.- The Multi-Frame Lighting Method: A Monte Carlo Based Solution for Radiosity in Dynamic Environments.- Wavelet Based Texture Resampling.- Modeling Textiles as Three Dimensional Textures.- Synthesizing Verdant Landscapes using Volumetric Textures.- Ray Tracing in Non-Constant Media.- Hierarchical Back-Face Computation.- The 3D Visibility Complex: A New Approach to the Problems of Accurate Visibility.- Conservative Radiance Interpolants for Ray Tracing.- Accurate Visibility and Meshing Calculations for Hierarchical Radiosity.- Color Section.

Human body animation: a survey

A survey of human body animation is presented dealing with its geometrical representation, motion control techniques and rendering. A classification of human body animation systems is presented according to different criteria.The human body movement notations are described and the different existing geometric models of the body and the face are analised and compared.The body and face control motion techniques are presented and discussed, as well as human body motion in its environment. Finally, the different problems of human body rendering are presented.

Visibility masks for solving complex radiosity computations on multiprocessors

This paper presents a strategy to handle very complex scenes for radiosity computation. Compared to other radiosity algorithms, our solution focuses on the ability to compute the radiosity in 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. We present an implementation of visibility masks on a distributed memory parallel computer (Intel Paragon XP/S).

A Survey of Inverse Surface Design From Light Transport Behavior Specification

Inverse surface design problems from light transport behavior specification usually represent extremely complex and costly processes, but their importance is well known. In particular, they are very interesting for lighting and luminaire design, in which it is usually difficult to test design decisions on a physical model in order to avoid costly mistakes. In this survey, we present the main ideas behind these kinds of problems, characterize them, and summarize existing work in the area, revealing problems that remain open and possible areas of further research.

Towards efficient parallel radiosity for DSM-based parallel computers using virtual interfaces

The paper presents the performance evaluation of a new technique for radiosity computation which aims at exploiting efficiently the different levels of a memory hierarchy of both sequential and parallel computers. Such ability is essential when dealing with complex environments having several millions of polygons. The principle of the technique is to split the initial environment into several sub-environments and compute the radiosity within each sub-environment. Exchange of energy between sub-environments is performed by means of virtual interfaces and visibility masks. The size of sub-environments can be adapted in order to fit into a cache or a local memory. The authors performed several experiments using an SGI Origin 2000 to show the effectiveness of the solution. It improves both the sequential and parallel execution of a progressive radiosity algorithm. The technique decreases the execution time on one processor of an SGI Origin 2000 by a factor of more than 5 and leads to a very good efficiency for complex environments (1 million of polygons) on a multiprocessor configuration.