Photometric and photorealistic representation of luminaires in 3D

In the fields of interior and exterior design, there is a large use of digital representation (the so-called photo-realistic renderings) in order to promote to possible clients what should be the final appearance of a designed environment. Very often, unfortunately, these representations are the result of empirical graphic representation based (in the best cases) on the experience of the designer and his ability to achieve images that are similar to what he plan to realize. However, when these previsional images are produced without a precise methodology in the management of virtual materials or the importing and integration of technical data of lighting products, the resulting digital images, although their strong visual impact, do not match the final appearance of the project a once put in place. In this paper, we aim to describe some accurate and practical techniques of modeling and representation of the lighting fixtures in a virtual project, while maintaining both photo-realism and photometric accuracy. These procedures can be used in the most common 3D software (modelling and representation). We will analyze some classes of luminaires that are available on the market (much diffused or with specific/complex features). We will describe techniques to couple the photometric data (in terms of distribution of intensities, colour of light and spatial orientation), the geometric model (optimized for the calculations), the simulation of the physics of materials (shaders) and the management of the final appearance of the lighting product. This contribution aims to help interior and exterior designers to achieve a digital model that is accurate in relation to the original product. This by using modelling and representation techniques that are quick, efficient and that suit better the typology of selected lighting fixture. This will help to the achievement of high visual impact digital images that also reflect the appearance that the designed space should have, with the chosen finishes and lighting products.