Spaciousness and Boundary Roughness

This article reports how strongly boundary roughness predicts impressions of spaciousness. In one experiment, 16 rooms with fractal walls were created in CAD simulations and 49 respondents rated the rooms in terms of spaciousness. In a second experiment, 16 respondents rated spaciousness for an additional 12 rooms with different wall systems. Fractal rooms with rough walls were judged as being more spacious than rooms with smooth walls, and opening bookshelves also made rooms seem more spacious. Thus, results from both studies indicate that boundary roughness makes rooms seem more spacious. Quantitative guidance is provided to assist future research.