John S. Gero, Scott Chase and Mike Rosenman (eds), CAADRIA2001, Key Centre of Design Computing and Cognition, University of Sydney, 2001, pp. 169-179. THE IMPACT OF COMPUTER-BASED DESIGN TOOLS FOR DAYLIGHTING SIMULATION AND PREDICTION FOR A BUILT ENVIRONMENT BENNY CHOW, SELINA LAM AND JIN-YEU TSOU The Chinese University of Hong Kong Hong Kong, China Abstract. This paper investigates the application of computer daylighting simulation to provide qualitative assessment and comparison for designers to improve the built environment especially for non- technical architecture students. A comprehensive study was carried out to evaluate different daylighting design tools and to identify the limitation of current systems in the academic field. The paper will focus mainly on the dynamic information exchange between scientific visualization and the design decision-making process. Both architectural design studio environment and practical design problems in the real world setting were experimented and evaluated. Two case studies are presented: a proposed gallery space for a museum, and a detail architectural design of a community church. Architectural design alterations are proposed, simulated and discussed. The recursive feedback of the designers are studied and documented. Through a combination of qualitative assessment and comparison, designers can evaluate and compare different design options in the computing environment before implementing in the real world situation. 1. Introduction The objective of this paper is to investigate the application of computer daylighting simulation to provide qualitative assessment and comparison for architectural designers to evaluate daylighting design alterations during the stage of schematic design and design development. Many people accept any output by a computer as scientific truth. There are different kinds of rendering applications that serve different purposes, and some of them are merely for illustration (Larson and Shakespeare, 1998; Ward, 1994; Tsou, 2000). Most designers use computer simulation or rendering software purely for illustrative purposes to show geometry and design scheme, not to scientifically predict lighting or the true appearance of the proposed architectural design under actual physical lighting conditions. The computer can be used to create