Isovists, enclosure, and permeability theory

Neurophysiological data and behavioral theory suggest that enclosure is a very important property of the environment. One technique for measuring enclosure is the mathematical construct of an isovist. An isovist is the set of points visible from a location. This paper reports analyses of 15 521 environments, ranging from cabin configurations in space stations to site plans for cities. Although results have been reported for twenty-five variables, it appears that only a few would be sufficient to distinguish between isovists. The most plausible variables are horizontal size and concavity. Judged enclosure was most strongly related to horizontal size, but it was also correlated with the variation in distance from the observation point to the isovist boundary, with boundary predictability, and with concavity. Numerical estimates of effect sizes are reported to assist in the efficient planning of future research.

Advances in visual diversity and entropy

Visual diversity is an important component of contemporary environmental design. Current issues on visual diversity include (a) how to measure it?, (b) what is the function between visual diversity and pleasure?, and (c) is the function between visual diversity and pleasure the same for different kinds of stimuli? Data are reported from twenty experiments covering 1126 stimuli and 1027 participants. The concept of statistical entropy is proposed as a measure of visual diversity. The correlation of ratings of visual diversity and entropy for environmental scenes was r = 0.87. Tenable relationships between pleasure and entropy for visual stimuli include linear and asymptotic but not the inverted U function. The type of stimulus strongly mediates the relationship between pleasure and entropy. Results from simple laboratory stimuli do not generalize to environmental scenes and, even within environmental scenes, the relationship between pleasure and entropy is positive for some types of scenes but negative for other types of scenes.

Slines, entropy, and environmental exploration

This paper addresses the question of how to create environments that people will want to explore. Four environmental properties (slines, entropy, floor area, and shape) were tested for exploration time in three experiments that included thirty-eight virtual environments and sixty participants. Slines had the strongest effect on exploration time ( r= 0.36), followed by entropy ( r= 0.34). Floor area and shape had much smaller effects on exploration time ( r= 0.10 and r= 0.09, respectively). Possibilities for future research are discussed.