The overall objective of DIAL-Europe is to favour the use of daylight in buildings. This tool promotes a "good" strategy from the very first stage of the design process. Version 4.0 allows you to : * Calculate Daylight Factor values on the work plane. (CIE overcast sky). * Estimate the Annual Daylight Sufficiency (time during which no artificial lighting is required) using climatic data (160 European cities). * Predict the number of Overheating Days. * Estimate the illuminance due to Artificial Lighting. * Optimise the performance of the room (Diagnosis function based on the use of fuzzy logic rules) * Compare your room with similar case studies stored in a database. * Improve your knowledge on lighting (multimedia lexicon)