Architecture / Mimarlık
Permanent URI for this collectionhttps://hdl.handle.net/11147/24
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Article Citation - WoS: 14Citation - Scopus: 15Photon Mapping in Image-Based Visual Comfort Assessments With Bsdf Models of High Resolution(Taylor and Francis Ltd., 2019) Grobe, Lars OliverData-driven models replicate the irregular Bidirectional Scattering Distribution Functions (BSDFs) of optically Complex Fenestration Systems in daylight simulation. RADIANCE employs the tensor tree to store the BSDF at high directional resolution. Its application in backward ray-tracing is however challenging, since the density of stochastic samples must match the model resolution. BSDF proxy and peak extraction address this problem, but are limited to cases when either the fenestration geometry, or the shape and direction of the transmission peak are known. Photon Mapping is proposed to efficiently sample arbitrary BSDFs from the known sun direction. The existing implementation in RADIANCE is extended to account for light sources and their reflections in the field of view, that are of particular importance for visual comfort assessments. The method achieves a high degree of accordance with ray-tracing, and reduces simulation times by approximate to 95% with data-driven models of high resolution.Article Citation - WoS: 14Citation - Scopus: 14Photon-Mapping in Climate-Based Daylight Modelling With High-Resolution Bsdfs(Elsevier Ltd., 2019) Grobe, Lars OliverVisual comfort assessments employing luminance-based metrics rely on efficient CBDM techniques for image synthesis. Data-driven BSDF models allow to isolate internal light paths in optically CFS from CBDM. Bidirectional photon mapping is proposed for the efficient sampling of such models in the calculation of the direct solar component in CBDM. The method allows accurate image synthesis for visual comfort assessments with only two calculation steps, achieving comparable accuracy as the established but complex 5PM. The validity of the approach is confirmed by comparison with backward ray-tracing. Its exemplary application to compare two CFS in terms of glare control demonstrates the importance to achieve reconcilability of conflicting targets such as view and glare control in daylighting. (C) 2019 Elsevier B.V. All rights reserved.Conference Object Comparison of Measured and Computed Bsdf of a Daylight Redirecting Component(EPFL Scientific Publications, 2015) Grobe, Lars Oliver; Noback, A.; Wittkopf, Stephen; Kazanasmaz, Zehra TuğçeThe Bidirectional Scatter Distribution Function (BSDF) of a selected Daylight Redirecting Component (DRC) is computed by a virtual goniophotometer using the enhanced photon map extension in Radiance, and compared to measured BSDF data. The DRC comprises a stack of tilted aluminum louvers with configurable inclination angle. The profile of the louvers is designed to control transmission depending on sun altitude, and to redirect light up towards the ceiling. The measured BSDF of the DRC is obtained from a scanning goniophotometer. For a sparse set of three source directions, the distribution is recorded at ≃ 250,000 receiver directions. The asymmetric angular resolution allows detailed observation of characteristic features in the distribution, which are assumed to persist over a range of source directions. For each pair of source and receiver directions in the measurement, the computed BSDF is generated from a model of the DRC, replicating the measurement with a virtual goniophotometer. The simulation relies only on the enhanced photon map extension for Radiance. The BSDF from measurement and simulation are compared qualitatively and quantitatively to discuss the degree of accordance. The presence of characteristic features and their topology is evaluated by comparing polar surface plots of the distributions and profiles of the scatter plane. The direct-hemispherical transmission is compared for each measurement and simulation. The RMSE of each computed distribution against the corresponding measurements is calculated to quantify the directionally resolved deviation. A high degree of qualitative accordance between the computed and the measured BSDF is achieved. Prominent features in the BSDF are represented by the model. A deviation of −6% to +15% is observed in a quantitative comparison of direct-hemispherical transmission by integration of computed and measured BSDF. The RMSE indicates higher deviations for lower source altitudes, where a direct transmission peak in the distribution is underestimated by the model. The method is proposed as a means to validate the capability of the enhanced photon map to predict transmission through DRC.Article Citation - WoS: 40Citation - Scopus: 51Three Approaches To Optimize Optical Properties and Size of a South-Facing Window for Spatial Daylight Autonomy(Elsevier Ltd., 2016) Kazanasmaz, Zehra Tuğçe; Grobe, Lars Oliver; Bauer, Carsten; Krehel, Marek; Wittkopf, StephenThis study presents optimization approaches by a recent Climate-Based-Daylight-Modeling tool, EvalDRC, to figure out the necessary area for a daylight redirecting micro-prism film (MPF) while minimizing the glazing area. The performance of a window in terms of spatial Daylight Autonomy (sDA) is optimized by its geometry and optical properties. Data implemented in simulation model are gathered through on-site measurements and Bidirectional-Scattering Distribution Function (BSDF) gonio-measurements. EvalDRC based on Radiance with a data driven model of the films' BSDF evaluates the window configurations in the whole year. The case to achieve an sDA of at least 75% is a South-facing window of a classroom in Switzerland. A window zone from 0.90 m to 1.80 m height provides view to the outside. The upper zone from 1.80 m to 3.60 m is divided into six areas of 0.30 m height in three optimization approaches including the operation of sunshades as well. First, the size of the clear glazing is incrementally reduced to find the smallest acceptable window-to-wall ratio (WWR). Second, micro-prism films are applied to an incrementally varying fraction the initial glazed area to determine the minimum film-to-window ratio (FWR). Finally, both approaches are combined for a minimum FWR and WWR. With clear glazing and WWR of 75%, the sDA of 70.2% fails to meet the requirements. An sDA of 86.4% and 80.8% can be achieved with WWR 75%, FWR 1/9 and WWR 50%, FWR 1/2 respectively. The results demonstrate the films' potential to improve the performance of windows with reduced WWR.