Simulation of Luminaires in Radiance: Verification Method

In the process of architectural design architects can use different software tools for modelling and simulation. These programs allow them to simulate imaginary buildings, and verify their intentions, preferences and respect of norms, in order to bring the resulting ambience closer to architects intentions. On the other hand, programs follow strictly defined geometrical and physical laws, which give quantitative accuracy to the project.

For modelling and simulation in architecture there is a great number of different computer programs available on the market, such as AutoCAD, 3DStudio Max, PovRay, Radiance, etc. All these programs offer similar possibilities for modeling of geometrical primitives, but their capability to simulate luminous ambiance of the building is different. Definition of luminous ambiance is rather complex, and it involves description of artificial (luminaires) and natural (sun, sky) light sources, building position and environment, and materials used for building interior and exterior. Lighting design programs are software tools for calculation and visualization of luminous ambiance.

Due to the complex nature of light, all lighting design programs, in the process of light modelling, involve some simplifying assumptions, which lead to some amount of calculation inaccuracy.

The aim of this paper is to propose a method for evaluation of the error introduced by computer simulation of luminaires. The method compares luminaire simulation results from Radiance2 software against results obtained from lighting calculation methods proposed by “Illuminating Engineering Society of North America” – IESNA.

Simulation of Luminaires in Radiance: Verification Method