Isometric measurands on perceived spaciousness: Exploring volumetric isovist

Alper Ünlü, Erincik Edgü, Mehmet Emin Şalgamcioğlu, Nevşet Gül Çanakçioğlu, Emir Atakan Yilmaz

Research output: Contribution to conferencePaperpeer-review

6 Citations (Scopus)


The isovists are essential hypothetical structures for understanding the visibility in space. Regarding the perception of space, volumetric visibility presents a complicated geometrical volume that may be considered as a polyhedron obtained from the optical arrays of the vantage point. Despite the stated importance of volume, the preference for two-dimensional approach was later emphasized to be highly pragmatic by the prominent researchers of the field considering the non-applicable and complex data analysis of isovist radials and accordingly the polyhedron structure within a three dimensional medium. Through an experimental case study, the research explores the extension of syntactic and semantic parameters of visual perception and helps to understand the dynamic nature of the volumetric visibility. Research uses semantic and syntactic data analyses based on the fixed vantage points in a medium to expose the differences in the spatial experience of users. Syntactic data obtained from a modified real environment, and semantic data obtained from the vantage point scenes derived from this environment are correlated. The research is based on four founding subjects of study, which are considered as the main factors in understanding the perception of spaciousness and openness. These factors are defined as isovist parameters, graph parameters, radial data parameters, and volumetric parameters. The selected environment of the case study is a part of a university building. For this study, ground and first floors are abstracted and simplified in the experiment’s virtual environment. Selected 16 vantage points from two floors had diverse variations in width, length and height, which are likely to cause different perceived spaciousness levels. Semantic evaluation is examined through an experimental research with 90 students from two different universities. The participants are asked to evaluate the feeling of spaciousness and openness in the virtual medium of 16 vantage points on a 5-point Likert type scale questionnaire. The last step of the methodology is composed of multiple regression analyses showing the effects of syntactic and spatial determinants of the virtual scenes and one-way-ANOVA analyses showing the effects of spatial experiences related to familiarity and educational background of the sample groups. Results of the research indicated that isovist area is highly correlated with spaciousness, meaning that wider spaces are perceived as more spacious. Higher connectivity values, having more possibility of expansions, lead to an idea of perceptual spaciousness. Volumetric visibility indicates that perception of spaciousness is directly related to the z-dimension. The amount of natural light in space has a positive effect on the participants’ semantic evaluations. The infinity value increases the amount of natural light, giving a feeling of wideness and providing a visual access to beyond. Previous experiences of students, familiarity with the space and educational background are highly effective on the perception of openness. In this research the psychological outcomes of visual perception through concepts of spaciousness and openness with three dimensional geometry of visibility are combined. By the help of novel methods of calculating volume, natural light and infinity values, the research presents a quantifiable data of comparison of semantic assessments with syntactic ones.

Original languageEnglish
Publication statusPublished - 2019
Event12th International Space Syntax Symposium, SSS 2019 - Beijing, China
Duration: 8 Jul 201913 Jul 2019


Conference12th International Space Syntax Symposium, SSS 2019

Bibliographical note

Publisher Copyright:
© 2019 Beijing JiaoTong University. All rights reserved.


  • Isovist
  • Openness
  • Spaciousness
  • Visual perception
  • Volumetric visibility


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