18|AULA cd HOW TO CHOOSE A LIGHTING DESIGN PROGRAM Text. Dr. Adrián Muros Alcojor. We have all faced this question at the beginning of a lighting project. Generally, the circumstances are diverse and sometimes not very analytical: ease of retrieval in the web, a colleague’s recom- mendation or on occasions, coincidence and urgency. To be sure, lighting design programs have operative characteristics that set them apart and make them more or less versatile, fast, intuitive or adequate depending on the intended application. Last year, the Institute of Construction Research of Denmark, jointly with the University of Aal- borg of Copenhagen, conducted an interesting work titled “Daylight calculations in practice. An investigation of the ability of nine Daylight simulation programs to calculate the daylight factor in five typical rooms”, which analyzes the operation of different daylight programs, establishing a comparative of the main results obtained. In this same investigation line, but referred to artificial lighting programs, we present the fo- llowing article carried out by the student of the Architecture School of Barcelona (Escuela de Ar- quitectura de Barcelona), Victor Jordá Bordoy. It consists of a comparative study of the lighting design and calculus programs most frequently used today, with the goal of pointing out the indivi- dual qualities as well as the aspects that set them apart. With this in mind, two different projects using each one of the programs, have been developed and a set of recommendations established. Without doubt, it will help us in our selection of the most adequate program for the lighting project we are developing. 1.Space data As to the introduction of files, Dialux and Relux allow import of DWG files from which you can build the space; this represents savings in time. Both have the option “import DWG” in the file menu and it is very important that you have previously placed the origin of coordinates in the left inferior vertex of the imported space because both programs will ask which point of the DWG file you want to coincide with the origin of coordinates of the work space. This way, all you have to do is make it coincide with the (0,0,0). Relux allows you to import layers while Dialux imports everything there is, as a single layer. Relux allows you to rotate the drawing while Dialux inserts it directly as drawn. Relux allows the imported drawing to become part of the work space simply by selecting the lines that you want to extrude to form the walls of the space. They have to form a closed outline without any openings, not even in the places where windows or doors would Gráfico isolux de Relux. be because these will be added later. In the event that one of the selected lines is a polyline, the program will automatically decompose it assigning each line a different parameter (“wall”). The curved lines will be automatically decomposed in an adequate number of segments that will act like different parameters. In Dialux, the imported drawing acts as an “intelligent” guideline at the time of drawing the space and when inserting the furniture and other elements, but you can never draw directly from it. The program creates by default a rectangular work space; when selecting the