"Crowd-based Illuminance Maps: Comparing Daylight Perception" by Muhammad Hegazy
Architectural Morphology Laboratory
Presentation from the 8th VELUX Daylight Symposium that took place in Paris on 9 October 2019. For more information please visit http://thedaylightsite.com & https://www.velux.com/veluxdaysinparis
Daylighting plays a key role in making space more sustainable and livable. Thus, using light simulation tools to assess daylight performance is considered as a vital stage in the design process of any building. Many studies focus on measuring the quantitative performance of daylighting through climate-based daylight modeling . However, it is also important to assess daylighting in more than mere numerical values and go further to address its subjective qualities and human-oriented experience . In this context, Virtual reality(VR) has found its way as an essential tool to a wide variety of applications in architecture, ranging from design and construction to project’s communication and collective decision-making pushed forward by the trending design democratization and participatory design directions .
Moreover, current advancements in VR hardware, as well as game engine technology prove promising horizons towards the realization of hyper-realistic VR environments, where users can not only immerse in but also interact with and give useful feedback. Many studies have addressed VR as an evaluative tool for daylighting, including the works of Chamilothori et al. and Rockcastle et al.. However, the authors argue three main limitations in the current related literature; Firstly, many studies on visual perceptions in VR are limited to small-scale, simple scenario environments, which lacks the complexity, vastness and variety required for validating daylighting subjective qualities on a wider scale. Secondly, reliance on head movement only rather than full walkability, which can limit user-environment interaction and thus bound accurate perception feedback. Another noticeable limitation is the mere use of verbal questionnaires to collect user responses rather than integrating gamified tasks into the virtual environment itself.
This paper describes an ongoing research that introduces a novel approach to measure human perception of daylight in virtual built environments through applying principles of immersion and gamification. Nevertheless, it investigates the consistency between user-reported brightness levels and physically-based illuminance simulations of the same space. To validate the methodology, a digital model of Kimbell Art Museum by Louis Kahn is created (Figure 1) , imported into Unreal Engine to setup location-based light rendering and interactive content, which offers the ability to walk freely, control daytime (sun position), switch on/off artificial lights, and saving snapshots. Then, through Head-Mounted Display and motion controllers, users are challenged to fulfill lighting-related tasks, this includes snapshotting best day lit spots, reporting poor day lit areas, as well as estimating floor brightness at given points on a 0-100 scale. Afterwards, a post-experience questionnaire is given to evaluate both system usability and daylighting quality. Finally, the collective user feedback is used to create a crowd-based light intensity maps for the floor plan at a given date/time, which are compared against similar empirical illuminance maps (in Lux) generated through physically-based simulations.
Muhammad Hegazy is currently a PhD candidate at the Architectural Morphology Laboratory in Osaka University, and holds a Master of Science in Environmental Design from Suez Canal University in Egypt. He has worked for Takenaka Corporation in Japan, and been invited as a speaker at the Architectural Association visiting school (AAVS) in Osaka. His doctoral research focuses on improving human-centered daylight performance in indoor environments. By comparing daylight perception in immersive virtual reality to other quantitative measurements, he aims to introduce a set of unified daylight performance metrics that consider both subjective and physical qualities of daylighting.