Eduardo Fernández

Technical Section: Inverse lighting design for interior buildings integrating natural and artificial sources

In this paper we propose a new method for solving inverse lighting design problems that can include diverse sources such as diffuse roof skylights or artificial light sources. Given a user specification of illumination requirements, our approach provides optimal light source positions as well as optimal shapes for skylight installations in interior architectural models. The well known huge computational effort that involves searching for an optimal solution is tackled by combining two concepts: exploiting the scene coherence to compute global illumination and using a metaheuristic technique for optimization. Results and analysis show that our method provides both fast and accurate results, making it suitable for lighting design in indoor environments while supporting interactive visualization of global illumination.

Inverse opening design with anisotropic lighting incidence

In architectural design, configuring opening shapes is a crucial element of daylight analysis. In this paper we present a new method which optimizes opening shapes to meet specified lighting design purposes. This novel approach treats the problem as an inverse lighting problem considering global illumination contributions and anisotropic lighting incidence, therefore any kind of sky distribution can be used as an external source of light. The key to our technique is in exploiting coherence to formulate a compact representation that can be tailored to optimization processes. The resulting reduction in processing time and efficiency in achieving optimal shapes along with the feasibility of dealing with anisotropic light sources are our key contributions. Graphical abstractDisplay Omitted HighlightsA new method for opening shape optimization that considers anisotropic lighting.Each opening is approximated by a set of pinholes.The light passing through each pinhole is modeled using a pair of hemi-cubes.The radiosity equation is modified to include anisotropic lighting.The new equation is used as part of an inverse lighting problem solver.

Computing urban radiation: A sparse matrix approach

Abstract Cities numerical simulation including physical phenomena generates highly complex computational challenges. In this paper, we focus on the radiation exchange simulation on an urban scale, considering different types of cities. Observing that the matrix representing the view factors between buildings is sparse, we propose a new numerical model for radiation computation. This solution is based on the radiosity method. We show that the radiosity matrix associated with models composed of up to 140k patches can be stored in main memory, providing a promising avenue for further research. Moreover, a new technique is proposed for estimating the inverse of the radiosity matrix, accelerating the computation of radiation exchange. These techniques could help to consider the characteristics of the environment in building design, as well as assessing in the definition of city regulations related to urban construction.

Visualizing the Infrared Response of an Urban Canyon Throughout a Sunny Day

The work presented here has consisted in placing a thermal camera in a street of the “Petit Bayonne,” one of the densest districts of French cities, in order to obtain a double sequence of photographs (shortwave) and thermographies (longwave) on a sunny day. The next step will be to repeat this sequence by numerical simulation to see how the measurements are used to calibrate the simulation and how the simulation can help to interpret the measurements.