Computers for Windows: Interactive Optimization Tools for Architects designing openings in walls (IOTA)

Abstract

Size, shape and disposition of windows in walls has long been an integral expression of style in architecture. As buildings have grown taller the relationships of the windows to the ground plane and to the surrounding environments have become more complex and difficult to predict. Traditionally architects have had to use their own knowledge, experience and feelings in the design of windows. There may be few, if any, scientific bases for their decisions. The difficulty in making good design decisions is compounded because many criteria for window design, such as daylight, sunlight, ventilation, sound, view and privacy have to be considered simultaneously. It is here that computers can help, on the one hand, by providing ‘expert knowledge’ so that architects can consult the cumulative knowledge database before making a decision, whilst on the other hand, evaluations of the decisions taken can be compared with a given standard or with alternative solutions. ‘Expert knowledge’ provision has been made possible by the introduction of hypertext, the advancement of the world wide web and the development of large scale data-storage media. Much of the computer’s value to the architects lies in its ability to assist in the evaluation of a range of performance criteria. Without the help of a computer, architects are faced with impossibly complex arrays of solutions. This paper illustrates an evaluation tool for two factors which are important to the window design. The two factors to be investigated in this paper are sunlighting and views out of windows. Sunlight is a quantitative factor that can theoretically be assessed by some mathematical formulae provided there is sufficient information for calculation but when total cumulative effects of insolation through the different seasons is required, in addition to yearly figures, a design in real-time evolution requires substantial computing power. Views out of windows are qualitative and subjective. They present difficulties in measurement by the use of conventional mathematical tools. These two fields of impact in window design are explored to demonstrate how computers can be used in assessing various options to produce optimal design solutions. This paper explains the methodologies, theories and principles underlying these evaluation tools. It also illustrates how an evaluation tool can be used as a design tool during the design process.