Some BIM-based lighting analysis tools, such as Elumtools (What Is ElumTools™?, 2016) and Dialux (Lighting Design Software DIALux, 2016), provide three-dimensional (3D) visualizations and walkthrough feature. However, this creates a barrier for collaboration between design teams and clients who are not familiar with interpreting numerical results, and this prevents the parties from understanding the energy requirements of different design options.
Such numerical data are used by experts who are experienced in interpreting such data. Energy consumption outputs are usually generated as numerical data and presented as complex graphs, documents, and/or tables (Sarhan & Rutherford, 2009 Hailemariam et al., 2010), which are separate from the visual context of the building (Hailemariam et al., 2010). Conventional simulated outputs often comprise quantitative and qualitative data, and the visualization features are based primarily on static two-dimensional (2D) images. Several existing commercial simulation tools that are compatible with BIM have been widely used in visualizing, identifying, and examining indoor lighting performance as well as simulating lighting energy consumption. The use of Building Information Modeling (BIM)-based computer simulation tools is growing rapidly, and such tools assist designers in making better decisions to reduce energy consumption and to create better lighting conditions for occupants. A reduction in lighting energy consumption can make a substantial contribution toward lowering the energy demand for buildings. (Book, 2016), 20 to 40% in large office buildings in China (Zhou et al., 2015), and 40% in commercial buildings in Japan (The Energy Conservation Center Japan, 2010). For example, lighting consumes approximately 16.7% of commercial building energy in the U.S. A major proportion of the total energy demand for buildings is electricity for lighting. The World Energy Council (World Energy Resources 2013 Survey, 2016) estimated that buildings account for nearly 40% of the total global energy consumption. (Benya et al., 2001) stated that lighting design primarily affects energy efficiency and lighting quality. The following determinants are amongst the factors that need to be considered in lighting design: daylight availability, aesthetics, lighting quality, and efficiency of lighting.
Lighting design relies on a combination of scientific, aesthetic, and human factors (Benya et al., 2001). BLDF allows users to interact with design objects, to change them, and to compare multiple design scenarios, and provides real-time lighting quality and energy consumption feedback. The developed system utilizes an interactive and immersive virtual reality (VR) environment to simulate daylighting and the illumination of artificial lights in buildings and visualizes realistic VR scenes using head mounted displays (HMD). The results of a case study revealed that BLDF supports design stakeholders to better perceive and optimize lighting conditions in order to achieve a higher degree of satisfaction in terms of lighting design and energy savings for future occupants.
This research proposes a method and develops a BIM-based lighting design feedback (BLDF) prototype system for realistic visualization of lighting condition and the calculation of energy consumption. Therefore, an incorrect interpretation by designers regarding the relationship between their desirable lighting design and energy feedback may occur. In addition, lighting energy consumption generated from traditional tools is often separated from the 3D virtual context of the building. Moreover, their visualization environments do not allow users to experience visual phenomena such as glare. Although such tools enable quantitative and qualitative analysis and visualization of indoor lighting, they do not provide an interactive environment between users and the design context. Lighting simulation tools are extending the functionality of Building Information Modeling (BIM) authoring software applications to support the lighting design analysis of buildings.