The use of daylight could give a significant contribution to the global performance of a building, not only in terms of energy saving but also for the comfort of the occupant, especially when the availability of solar radiation coincides with the light demand. Due to the fact that physical parameters for lighting are the same as scale, it is possible to evaluate the behaviour of light in a building using a scale model that reproduces exactly the geometry of the space and the surface properties of the materials. By means of a scale model tested in an artificial sky simulator that reproduces the characteristic luminance distribution of the sky, this paper provides the study of a relationship between the architectural components of an atrium (geometry, material properties, the fenestration system, the atrium roof) and the daylight conditions inside the buildings. The final aim is to produce a comparison between the experimental values obtained with the scale model and the numerical values come from Radiance. Thanks to it, it is possible to apply a preliminary evaluation of the basic design choices in order to consider the possible alternative building configurations