Isotropic clustering for hierarchical radiosity - implementation and experiences

Although Hierarchical Radiosity was a big step forward for finite element computations in the context of global illumination, the algorithm can hardly cope with scenes of more than medium complexity. The reason is that Hierarchical Radiosity requires an initial linking step, comparing all pairs of initial objects in the scene. These initial objects are then hierarchically subdivided in order to accurately represent the light transport between them. Isotropic Clustering, as introduced by Sillion, in addition creates a hierarchy above the input objects. Thus, it allows for the interaction of complete clusters of objects and avoids the costly initial linking step. In this paper, we describe our implementation of the isotropic clustering algorithm and discuss some of the problems that we encountered. The complexity of the algorithm is examined and clustering strategies are compared

A Monte Carlo method for accelerating the computation of animated radiosity sequences

Realistic rendering animation is known to be an expensive processing task when physically-based global illumination methods are used in order to improve illumination details. This paper presents an acceleration technique to compute animations in radiosity environments. The technique is based on an interpolated approach that exploits temporal coherence in radiosity. A fast global Monte Carlo pre-processing step is introduced to the whole computation of the animated sequence to select important frames. These are fully computed and used as a base for the interpolation of all the sequence. The approach is completely view-independent. Once the illumination is computed, it can be visualized by any animated camera. Results present significant high speed-ups showing that the technique could be an interesting alternative to deterministic methods for computing non-interactive radiosity animations for moderately complex scenario

A New Mathematical Development for Radiosity Animation with Galerkin

International audienceCombining animation and global illumination constitutes, at present, a true challenge in computer graphics, especially when light sources move in a complex scene because the entire illumination has to be recomputed. This paper introduces a new algorithm, based on the Galerkin method, which can efficiently manage any moving surface -even light source- to compute animation sequences. For each new frame of a sequence, we take into account the continuous property of the moves to determine the necessary energy differences between the previous global illumination solution and the new one. Based on a mathematical development of the form factor, this new approach leads to an efficient and simple algorithm, similar to the classical progressive refinement algorithm, and which computes animated sequence about three times faster

Many-Light Real-Time Global Illumination using Sparse Voxel Octree

Global illumination (GI) rendering simulates the propagation of light through a 3D volume and its interaction with surfaces, dramatically increasing the fidelity of computer generated images. While off-line GI algorithms such as ray tracing and radiosity can generate physically accurate images, their rendering speeds are too slow for real-time applications. The many-light method is one of many novel emerging real-time global illumination algorithms. However, it requires many shadow maps to be generated for Virtual Point Light (VPL) visibility tests, which reduces its efficiency. Prior solutions restrict either the number or accuracy of shadow map updates, which may lower the accuracy of indirect illumination or prevent the rendering of fully dynamic scenes. In this thesis, we propose a hybrid real-time GI algorithm that utilizes an efficient Sparse Voxel Octree (SVO) ray marching algorithm for visibility tests instead of the shadow map generation step of the many-light algorithm. Our technique achieves high rendering fidelity at about 50 FPS, is highly scalable and can support thousands of VPLs generated on the fly. A survey of current real-time GI techniques as well as details of our implementation using OpenGL and Shader Model 5 are also presented

Parallel Hierarchical Radiosity on Hybrid Platforms

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-011-0592-6[Abstract] Achieving an efficient realistic illumination is an important aim of research in computer graphics. In this paper a new parallel global illumination method for hybrid systems based on the hierarchical radiosity method is presented. Our solution allows the exploitation of systems that combine independent nodes with multiple cores per node. Thus, multiple nodes work in parallel in the computation of the global illumination for the same scene. Within each node, all the available computational cores are used through a shared-memory multithreading approach. The good results obtained in terms of speedup on several distributed-memory and shared-memory configurations show the versatility of our hybrid proposal.[Resumo] Acadar unha eficiente iluminación realista é un importante obxectivo no campo dos gráficos por computadora. Neste traballo preséntase un novo método de iluminación global paralelo para sistemas híbridos baseado no modelo de radiosidade jerárquica. A nosa solución permite a explotación de sistemas que combinen nodos de cómputo independentes con múltiples núcleos de execución en cada nodo. Deste xeito, varios nodos traballan en paralelo na computación da iluminación global dunha mesma escea. Dentro de cada nodo, todos os núcleos computacionais dispoñibles son aproveitados mediante unha aproximación multifío en memoria compartida. Os bos resultados obtidos en canto a aceleración en distintas configuracións de memoria compartida e distribuída dan mostra da versatilidade da nosa proposta híbrida.Xunta de Galicia; INCITE08PXIB105161PRMinisterio de Educación y Ciencia; MEC TIN 2010-16735Xunta de Galicia; 08TIC001206P

Hardware Acceleration of Progressive Refinement Radiosity using Nvidia RTX

A vital component of photo-realistic image synthesis is the simulation of indirect diffuse reflections, which still remain a quintessential hurdle that modern rendering engines struggle to overcome. Real-time applications typically pre-generate diffuse lighting information offline using radiosity to avoid performing costly computations at run-time. In this thesis we present a variant of progressive refinement radiosity that utilizes Nvidia's novel RTX technology to accelerate the process of form-factor computation without compromising on visual fidelity. Through a modern implementation built on DirectX 12 we demonstrate that offloading radiosity's visibility component to RT cores significantly improves the lightmap generation process and potentially propels it into the domain of real-time.Comment: 114 page