PLEA 2008 – 25 th Conference on Passive and Low Energy Architecture, Dublin, 22 nd to 24 th October 2008 354: Composing with Light: An inside-out Evaluation of the Role of Intuition and Simulation throughout the Design Process Zigurds Greivulis 1,2 , Mehlika Inanici 1* Department of Architecture, University of Washington, Seattle, USA 1* inanici@u.washington.edu Current address: Raunas 45/4-195, Riga, Latvia 2 Abstract This paper demonstrates a design process, in which intuition and building performance simulation are integrated to guide and inform the decisions in the conceptual and developmental phases. The main sustainable strategy has been identified as daylight harvesting for the refurbishment of an artificially lit pavilion into a library. "Light as an image of nature” is a concept that refers to the patches of the sunlight penetrating thru the branches and leaves of trees. This concept is used as the deriving concept in design, where perceptional qualities of space and light are orchestrated with optimal visual performance and visual comfort. Quantitative criteria (illuminance values, daylight factor, daylight autonomy, luminance distributions, and glare analysis) and visual appraisal are used for design evaluation. The resulting design process is iterative, where simulation is used extensively to provide feedback for accelerating and improving the design decisions. Keywords: daylighting; building performance simulation, perceptional qualities of lighting; daylight autonomy; visual comfort; architectural design process 1. Introduction Building performance simulation has matured significantly in the recent decades. Increased accuracy and fidelity of simulations opened up many opportunities for deployment of better performance analysis tools, techniques, and metrics. However, most of these tools are employed at later design phases: Their usage requires expertise, often acquired through consultancy. Their predictability power depends upon the physically based modeling of geometry, material properties, and other information that can only be determined in later stages of design. Therefore, simulation is used to test whether certain performance criteria are fulfilled after the design strategies are developed and/or most of the decisions are finalized. As a result, its impact on the final design is limited. Recently, designer friendly simulation tools that provide both visual and numerical feedback have emerged to promote the earlier use of the analytical tools in the design process. However, wide scale adoption and integration into the design process is a challenging issue: The synthesized design solution may be not the most rational alternative, rather the most successful mediation between conflicts, priorities, concepts, and affirmations [1]. Simulation based design approaches raise indirect skepticism as the main intent of any architectural design cannot be reduced to fulfill numerical criteria [2]. This paper demonstrates a design process that incorporates both intuitive and scientific approaches. The underlying ideas are as follows: (i) Conception of a building design is guided by the goals and constraints of the project, and driven by the intuitive approaches of the design team (ii) Analytical approaches employed throughout the design processes help architects to envision the performance of their designs, accelerate and improve the design decisions, and reduce the uncertainty of the outcome; (iii) Computational approaches enable analysis with detail, flexibility, and rigor that may be infeasible or impossible to achieve with traditional analysis tools and techniques. 2. Design Project The design project used to demonstrate the role of intuition and simulation is a proposal to refurbish the existing “Fun Forest” pavilion in Seattle Center (Fig. 1) as a public library. Seattle Center was originally designed for World Expo and today it includes iconic buildings such as the Space Needle (1962) and the Experience Music Project (2001). It is a major gathering place for public events and festivals. The library is proposed to enhance the existing civic character of the Seattle Center. The aspiration is to design the library as a daylit space: The design criteria include the fulfillment of quantitative lighting requirements for libraries. However, the deriving design concept is to match the perceptional qualities of light patterns penetrating thru the trees, inspired by Pacific North-West landscapes. This inspiration is concurrent with Millet’s concept of “light as the image of nature” [3]: