An interactive approach to investigate brightness perception of daylighting in Immersive Virtual Environments:Comparing subjective responses and quantitative metrics

Daylighting plays an eminent role in the performance of indoor environments and their occupants,thus necessitating the need to investigate daylight perception of potential occupants at early design stages.The present study introduces an interactive approach to collect and visualize brightness perception of daylighting in a large-scale immersive virtual environment using a game engine as a daylight simulation tool.The developed system allows users to explore building models freely at different day times set in virtual reality and report their perceptions in real time.Following a validation study(N=36)to investigate the consistency of brightness perceptions in a real environment and its virtual replica,a set of 24 participants were recruited to use the system to report their brightness perception in a virtual model of a daylit art museum,through snapshotting the scenes where they perceive as one of the following in terms of daylighting:(very dark,dark,bright,or very bright).Using an output of 419 snapshots,a"Perceptual Light Map"(PLM)was developed to visualize the collective brightness perception of participants as a heat map.Subjective responses were found to be positively correlated with four daylight metrics,with the highest correlation to mean luminance and the lowest to luminance ratio.The findings of this exploratory study represent a step towards a user-oriented supplement tool to the existing quantitative daylight metrics,validating game engines’adequacy as a daylight simulation tool,and illustrating the potentials of immersion and interaction principles for the perception of daylit spaces in virtual reality.

Geovisualization with immersive virtual environments in theory and practice

Virtual reality(VR)is a frequently emphasized issue on the Digital Earth(DE)agenda.While current DE research is more engaged in the technical aspects of VR applications,this paper focuses on what is possible with immersive virtual environments(IVE)from the user’s perspective.After a brief discussion of spatial presence and embodiment in the context of IVE,both concepts will be merged into a geovisualization immersion pipeline(GIP)as a framework with which to systematically link technical and cognitive aspects of IVE.We will then analyze the general criteria that must be met by IVE in order to facilitate the experience of spatial presence.Adapting these criteria to the special requirements of geospatial data,a definition of geovisualization immersive virtual environments(GeoIVE)is formulated.Finally,the theoretical considerations of this paper are set into practice,using a GeoIVE of a coral reef ecosystem as an example.As we shall see,while GIS do not provide data models or data compatibility for direct visualization of GeoIVE on VR output devices,game engines can serve as middleware to fill this gap.

Measuring user preferences and behaviour in a topographic immersive virtual environment(TopoIVE)of 2D and 3D urban topographic data

This paper investigates user preferences and behaviour associated with 2D and 3D modes of urban representation within a novel Topographic Immersive Virtual Environment(TopoIVE)created from official 1:10,000 mapping.Sixty participants were divided into two groups:the first were given a navigational task within a simulated city and the second were given the freedom to explore it.A Head-Mounted Display(HMD)Virtual Reality(VR)app allowed participants to switch between 2D and 3D representations of buildings with a remote controller and their use of these modes during the experiment was recorded.Participants performed mental rotation tests before entering the TopoIVE and were interviewed afterwards about their experiences using the app.The results indicate that participants preferred the 3D mode of representation overall,although preference for the 2D mode was slightly higher amongst those undertaking the navigational task,and reveal that different wayfinding solutions were adopted by participants according to their gender.Overall,the findings suggest that users exploit different aspects of 2D and 3D modes of visualization in their wayfinding strategy,regardless of their task.The potential to combine the functionality of 2D and 3D modes therefore offers substantial opportunities for the development of immersive virtual reality products derived from topographic datasets.