Time Handling in Inverse Daylighting for CAAD

Abstract

This paper presents an integration of time dimension in an inverse natural lighting model. This model allows to aid the design of building openings starting from the designed volume and lighting intentions. As natural lighting evolves according to the hour of the day and the day of the year, it is necessary to take into account that the lighting intentions expressed by designers might evolve through time. The problem is to choose the way of mixing the lighting intentions or the solutions of inverse lighting simulation in order to produce useful results for designers. We propose to compute separatly individual inverse lighting at each time step in order to get an individual evaluation map, and to combine the results in a final time evaluation map. This time evaluation map allows to read easily the addition of several inverse lighting simulations, and to compute an opening shape which is intended to be used as a basis for the opening design. Our method is illustrated through test cases in order to show the inverse lighting process with time integration.