The Hemisphere Radiosity Method: A Tale of Two Algorithms

Spencer, Stephen N.

doi:10.1007/978-3-662-09287-3_9

Cited by 12 publications

(6 citation statements)

References 3 publications

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“…They have concluded that the hemicube algorithm is the fastest among these algorithms, but the accuracy of the hemicube algorithm stagnates when it is used for a large-scale model which includes a large number of finite elements. On the other hand, by modifying a hemisphere algorithm developed by Spencer [11], Doi [10] could generate graphics of the same quality as the graphics generated by the original hemisphere algorithm; the modified algorithm took only half the CPU time of the hemisphere algorithm. Their algorithm is based on the projection of elements to the bottom plane of a hemisphere through its great circle.…”

Section: Form Factormentioning

confidence: 99%

Performance of hemisphere algorithm for fast form factor calculation

Yamada

Shinoda

Takizawa

2009

Heat Trans. Asian Res.

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A fast and accurate algorithm is required for carrying out radiative heat transfer simulations designing thermally efficient devices. This paper describes the performance of the hemisphere algorithm, which was originally developed for fast form factor calculation for obtaining photorealistic three-dimensional computer graphics. We compare the performance of the hemisphere algorithm with that of two conventional algorithms that are widely used for radiative heat transfer simulations. The hemisphere algorithm is found to be significantly faster than the other algorithms, but it has an absolute error of 1.0 × 10 -5. In addition, the result indicates that the hemisphere algorithm is suitable for simulating the trial and error process in the practical analysis of large-scale models due to its tolerable visualization of form factor distribution.

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Section: Form Factormentioning

confidence: 99%

Performance of hemisphere algorithm for fast form factor calculation

Yamada

Shinoda

Takizawa

2009

Heat Trans. Asian Res.

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“…The number of projections were further reduced by using a single-plane projection (e.g. (Sillion and Puech, 1989)) or hemisphere (base) projections which, to our knowledge, were first proposed by (Spencer, 1992). In this case the projection is a simple normalization process and clipping can simply be performed against the base plane of the hemisphere.…”

Section: Projectionsmentioning

confidence: 99%

“…In this case the projection is a simple normalization process and clipping can simply be performed against the base plane of the hemisphere. To ensure an accurate projection, (Spencer, 1992) calculates the degree of the arc between pairs of points projected onto the hemisphere basis and uses this value to calculate intermediate points along the edge. A scan-conversion algorithm is then used to Table 1: Performance comparison between a CPU radiosity solver t cpu and our implementation (t gpu,cube for the hemicube and t gpu,sphere for the non-linear hemispherical projection with the speed-up in brackets).…”

Section: Projectionsmentioning

confidence: 99%

An Empirical Evaluation of a Gpu Radiosity Solver

Wallner

2010

Proceedings of the International Conference on Computer Graphics Theory and Applications

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This paper presents an empirical evaluation of a GPU radiosity solver which was described in the authors previous work. The implementation is evaluated in regard to rendering times in comparision with a classical CPU implementation. Results show that the GPU implementation outperforms the CPU algorithm in most cases, most importantly, in cases where the number of radiosity elements is high. Furthermore, the impact of the projection-which is used for determining the visibility-on the quality of the rendering is assessed. Results gained with a hemispherical projection performed in a vertex shader and with a real non-linear hemispherical projection are compared against the results of the hemicube method. Based on the results of the evaluation, possible improvements for further research are pointed out.

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“…Such algorithms employ either analytical or probabilistic techniques, broadly referred to as Radiosity and Monte Carlo methods, respectively [4]. Prominent radiosity-based methods include the hemisphere method [5], the hemicube method [6] and adaptive integration [7]. Different implementations of the Monte Carlo method have been proposed since the 1960s.…”

Section: Introductionmentioning

confidence: 99%

Calculation of View Factors for Building Simulations with an Open-Source Raytracing Tool

et al. 2022

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Longwave radiative heat transfer is a key determinant of energy consumption in buildings and view factor calculations are therefore required for the detailed simulation of heat transfer between buildings and their environment as well as for heat exchange within rooms. Typically, these calculations are either derived through analytical means or performed as a part of the simulation process. This paper describes the methodology for employing RADIANCE, a command-line open-source raytracing software, for performing view factor calculations. Since it was introduced in the late-1980s, RADIANCE has been almost exclusively employed as the back-end engine for lighting simulations. We discuss the theoretical basis for calculating view factors through Monte Carlo calculations with RADIANCE and propose a corresponding workflow. The results generated through RADIANCE are validated by comparing them with analytical solutions. The fundamental methodology proposed in this paper can be scaled up to calculate view factors for more complex, practical scenarios. Furthermore, the portability, multi-processing functionality and cross-platform compatibility offered by RADIANCE can also be employed in the calculation of view factors.

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The Hemisphere Radiosity Method: A Tale of Two Algorithms

Cited by 12 publications

References 3 publications

Performance of hemisphere algorithm for fast form factor calculation

Performance of hemisphere algorithm for fast form factor calculation

An Empirical Evaluation of a Gpu Radiosity Solver

Calculation of View Factors for Building Simulations with an Open-Source Raytracing Tool

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