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www.itcon.org - Journal of Information Technology in Construction - ISSN 1874-4753
ITcon Vol. 28 (2023), Anifowose et al., pg. 539
ENERGYSIM: TECHNIQUES FOR ADVANCING BUILDING ENERGY
EDUCATION THROUGH IMMERSIVE VIRTUAL REALITY (VR)
SIMULATION
SUBMITTED: April 2023
REVISED: August 2023
PUBLISHED: September 2023
EDITORS: Chansik Park, Nashwan Dawood, Farzad Pour Rahimian, Akeem Pedro
DOI: 10.36680/j.itcon.2023.028
Hassan Anifowose, Ph.D.
Department of Construction Science, Texas A&M University
Hassancortex@tamu.edu
Kifah Alhazzaa, Ph.D. Candidate
Department of Architecture, Texas A&M University
Department of Architecture, Qassim University, Qassim 52571, Saudi Arabia
alhazzaa@tamu.edu
Manish Dixit, Associate Professor
Department of Construction Science, Texas A&M University
mdixit@arch.tamu.edu
SUMMARY: An important practice for reducing the effects of global warming is the design and construction of
energy-efficient buildings. In design education, the full comprehension of thermal behavior in buildings based on
their geometry and material composition is required. The complexity of energy simulation principles, vis-a-vis the
number of elements that impact the energy loads, their linkages, and their relationships to one another all combine
to make this a challenging subject to absorb. Virtual Reality (VR) provides an immersive way to learn the concepts
of building energy responses; however, the development of VR applications for education is difficult due to the
knowledge, skill, and performance resource-related gaps. Unoptimized VR applications can adversely impact
learning if user experiences are broken due to performance lags. This research, therefore, explores VR as a
teaching tool for building energy education while showcasing the development process toward a visually accurate
simulation and performant application. We developed EnergySIM; a multi-user VR building energy simulation
prototype of the famous Farnsworth House. Using this prototype, we document rigorously tested development
workflows for improved VR game performance, high visual fidelity, and user interaction, the three key factors
which positively contribute to user knowledge retention. The study combines menu-driven interaction, virtual
exploration, and miniature model manipulation approaches with the aim of testing user understanding and
knowledge retention. Highlighted results provide reduced barriers of entry for educators towards developing
higher quality educational VR applications. EnergySIM showcases pre-simulated building exterior surface
heatmaps response from four seasons (winter, summer, fall, and spring) alongside an all-year-round sun-hour
scenario. Four different material pre-simulated scenarios (single glazing, double glazing, concrete, and wood) for
interior atmospheric temperature mapping are also explored. Preferred interaction methods are documented by
allowing users’ visual appraisal of alternative building materials based on insulation capacity or resistance to
heat flow (R-value). The significance of this work lies in its potential to revolutionize how students, designers, and
instructors approach building energy education in today’s world. EnergySIM provides a hands-on and visually
engaging learning experience towards the enhancement of knowledge retention and understanding. It pushes the
boundaries of development for visual fidelity using geometry/mesh modeling input from various software into
game engines and optimizing game performance using the HTC Vive Pro Eye and Meta Quest Pro headsets.
KEYWORDS: Virtual Reality, Design Education, Building Energy, Simulation, Visualization, Energy Efficiency
REFERENCE: Hassan Anifowose, Kifah Alhazzaa, Manish Dixit (2023). ENERGYSIM: techniques for advancing
building energy education through immersive virtual reality (VR) simulation. Journal of Information Technology
in Construction (ITcon), Special issue: ‘The future of construction in the context of digital transformation (CONVR
2022)’, Vol. 28, pg. 539-554, DOI: 10.36680/j.itcon.2023.028
COPYRIGHT: © 2023 The author(s). This is an open access article distributed under the terms of the Creative
Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
ITcon Vol. 28 (2023), Anifowose et al., pg. 540
1. INTRODUCTION
There is an incumbent need to increase awareness of energy usage and waste by consumers as the average person
is typically unable to mentally picture the amount of energy they consume (Haefner et al., 2014).
On a macro level, designers need to be educated on the impact of building geometry, orientation, and choices of
construction materials on energy consumption with respect to climate change and sustainability. Industrialized
countries' energy-related carbon emissions constitute thirty-six percent of their total emissions (Metz et al., 2007).
The demand for energy is growing at a very rapid rate due to the rising standard of living and population (Hafeznia
et al., 2017). A significant amount of a building's overall energy usage is attributable to the process of cooling or
heating the interior space in order to satisfy the occupants' desired thermal conditions (John Dulac, 2020). A
revolutionary shift in energy management with the primary emphasis being placed on the energy efficiency of
buildings should be one of the primary goals of future generations, both from an economic and an environmental
point of view (Lin et al., 2016).
The complexity of energy simulation principles makes the subject very challenging to understand even to design
education students. Recognizing the most important technologies, as well as their existing and potential future
growth in the market and research, is crucial in the construction sector due to the relevance of energy consumption
(Aslani et al., 2017). The complexity of energy modeling concepts, the number of factors that affect the conclusion,
and their links and interactions make this a difficult topic to comprehend. It, therefore, becomes crucial to research
the possibility of enhancing learning in design education by the exploration of teaching techniques that new
technologies offer. This provides motivation for the development of EnergySIM in the attempt to help learners
combine visual, auditory, and kinesthetic learning modalities.
Immersive Virtual Reality (VR) experiences allow learners to embody their presence in simulated environments.
This level of immersion helps learners better understand complex concepts such as building energy simulations.
This can help reduce misinterpretations of conventionally presented energy data. Computer screens and building
energy software do not provide this high level of immersion where users can experience improved spatial
understanding, visualize accurate geometric representation in terms of scale, and better interpret spatial
relationships of objects to one another. VR provides a powerful way of energy visualization that is effective and
easy to grasp; providing an easier pathway for design education. This paper offers a step-by-step approach toward
the development of a VR application which is aimed at simplifying the learning curve of complex subjects.
1.1 VR in Architectural Education
Remote learning was widely used when the world was fighting a pandemic, and BIM + VR gave a foundation for
creating remote learning situations for architecture students. For students in architectural education and their
institutions, visiting architectural predecessors is expensive. Additionally, because local visits lack layers of
involvement (Kharvari & Höhl, 2019), the memory of learning objectives often differs between students depending
on several additional factors. The research also suggests that, in a gaming setting, VR enhances spatial memory
and recall of such virtual worlds of architectural predecessors. However, there is little data on how reproducing
such precedents can enhance learning results, thus further research is needed to firmly establish this.
Bourdakis contends that constructing spaces in virtual worlds naturally turns into an architectural difficulty and
that design itself is a problem in architectural education (Bourdakis & Charitos, 1999). The study made clear the
necessity of changing the course of architectural education to produce a new generation of virtual environment
architects.
There are few programs in architecture schools nowadays that teach students how to design in virtual environments
(VE). This is a potential opportunity to expand the use of VEs by exploring architectural education and the design
of spaces all within VEs.
According to Kamath, it has been demonstrated that pushing VE learning further in tutored settings "benefits
young architects on their initial step towards comprehending the essence of architecture" (Kamath et al., 2012).
Availability of talent is now a barrier to the creation of content for augmented reality (AR) and virtual reality (VR).
A special set of abilities is needed for development, including proficiency in 3-D modeling and rendering, video
knowledge, problem-solving, interaction design, storytelling, and user experience design. The specialty skill pool
experiences a retention issue as a result (Cacho-Elizondo et al., 2018).
ITcon Vol. 28 (2023), Anifowose et al., pg. 541
1.2 VR in Construction Education
Teaching methods place significant restrictions on how building composition is studied in construction education
classrooms. This inspires our study concept to use BIM and a virtual building lab environment to give students a
platform to apply their knowledge and abilities to address education challenges in the real world. However, many
configurations for such environments need to be tested to see which one offers flexibility and enhances learning
(Ghosh, 2012). Ghosh considered the design of an experimental space that examines participation in a virtual
learning environment. 3D game-based VR continuously shows that it supports learning especially in Construction
Engineering Education and Training (CEET). These new technologies continue to alter instruction from being
teacher-centered to student-centered (Wang et al., 2018).
According to Goedert, the gamification of construction learning is one way to continually engage the younger
generation (Generation Y) in the construction sector who find it challenging to engage with conventional
educational techniques (Goedert et al., 2011). This paves the way for the investigation of interactive virtual
construction education with the intention of reducing dangers associated with repetitive construction. Scaling up
gamification systems can offer instruction and training to a larger population of students and workers who study
equipment and construction scheduling, based on a simulated environment that is designed to reflect the real-world
scenarios (Goedert et al., 2011). One benefit of VR in construction education is that it allows students to access
materials used to teach courses repeatedly while teachers can continuously enhance such materials over time
(Shiratuddin & Sulbaran, 2006). The technology shown by Immersive Learning in a Virtual Reality Environment
(ILVRE) study, improved students' capacity to have a high degree of control over learning speed and navigation
via VR environments in addition to the chance to interact with models within a 3D virtual construction site. This
background provides motivation for the EnergySIM development and study.
2. RELATED WORKS
This real-world problem of providing high fidelity visual simulation of building energy usage has been a subject
of interest however, it has not been researched widely. Researchers have used tools such as Energy Experience
Lab (EELab) for real-time visualization of power consumption in public buildings with the aim of generating
insights from complex data. This application was considered for potential users such as facility owners and energy
consultants at the post-occupancy phase of a project (Haefner et al., 2014). This provided the groundwork for
further investigation however, using more recent education tools such as Virtual Reality to explore and develop
new frameworks.
2.1 Current development frameworks
Considering the upward adoption of Virtual Reality techniques in developing design education content, researchers
have previously explored workflows for best daylighting and lighting analysis. Software such as Autodesk Insight
have been used with Revit to visualize energy analysis containing numerical data (Ergün et al., 2019). Although
this method provides raw data files useful for numerical data analysis, we found this method inadequate for detailed
visual results hence the suggested method in this paper. Previous works also show that selecting the right tools for
VR development is not the only important aspect. Knowing the end user, outlining the problem, expectations and
end goals are factors which must be considered alongside the deployment platform (desktop or mobile), integration
methods and development time (Al-Adhami et al., 2018). In this paper, we provide a clear detail of methods and
best practices for developing improved visual content for building energy simulation in VR, useful for design
education cases. EnergySIM is developed for entry level design students with difficulty of learning building energy
response. Expected outcomes include increased levels of understanding about the impact of building forms and
construction material choices on energy consumption in buildings.
2.2 Proven Workflows in VR
According to a previous research conducted in our laboratory, the benefits of building a VR prototype outweighs
verbal explanation and with increased realism, usability can be improved due to near-reality experiences
(Anifowose et al., 2022). Established workflow in previous research tested VR precision features such as snap-to-
position and snap-to-angle for task-based systems providing ease of entry into developing such learning content.
The previously published development approach is adopted for the prototype discussed in this paper. Various
workflows were also studied (Beach, 2018; Nugraha Bahar et al., 2014), showing attempts to create efficient CAD
ITcon Vol. 28 (2023), Anifowose et al., pg. 542
data for thermal simulation and visualization in VR. Thermal simulation software are not typically developed to
showcase results in useful geometry but mostly in charts or graphs (Nugraha Bahar et al., 2014). Recent software
platforms however have embraced visual representations, however, there are still difficulties surrounding their
usability in cross-software developments. Methods to solve data transfer problems have been developed however,
the challenge about visual clarity remains unsolved. Architectural design students tend to be highly visually
inclined to learning (Demirkan, 2016; Mostafa & Mostafa, 2010) therefore, we are proposing a more defined
approach to showcasing building energy simulation with a focus on visual and interactive development.
2.3 BIM+LOD – Farnsworth House
By showing off the investigation of architectural precedents and duplicating the assembly of the same with various
game difficulty levels that correlate with various BIM levels of development, we evaluated the gamification
hypothesis in a game design presentation in virtual reality (LODs). Students were among the participants, and they
were asked to show it and talk about how using a gamified approach to teaching architecture may help with content
creation and implementation. The Farnsworth House was utilized for this investigation.
This idea was demonstrated in an earlier VR game design, by demonstrating the investigation of architectural
predecessors and duplicating the assembly of the same with varied BIM levels of development (LODs). The
abstract concept addition for the architectural antecedent, according to the demonstrators' feedback, improved their
knowledge after the exploration and made the assemblage process easier. Snap features helped to increase
interactivity and interest during the game's assembly phase. The demonstration revealed the potential for raising
learning goals in an ongoing gamified construction assemblage research.
The inability to create custom scripts and the difficulties in retaining all geometry data in BIM files migrated to
Unity game engine were limitations encountered during the game's development. The development of mechanics
to prevent users from creating an excessive number of items inside the game presented more difficulties.
The study revealed that adding specialized VR game features during assembly and creating geometric abstract
concepts for game material may be instrumental to students’ increased understanding of architectural precedents.
It has been demonstrated in our ongoing gamification study that these characteristics boost users' confidence for
comparable activities in real-world assemblies. These features also resulted in increased intuition levels in users
as they interacted with the components during assembly which also contributed to their ability to finish the tasks.
An object spawning and object destruction system is important for game optimization which reduces the need to
consistently keep large files present in the game scenes. The experiment's findings showed that including abstract
notions in places more than just building geometry improves memory and knowledge retention. During the
exploration stage, players also reported a deeper understanding, based on the in-game audio and video
commentary.
2.4 BIM+VR Construction Lab
A VR Construction Lab prototype which is a spinoff of the BIM+LOD prototype was developed in a related study.
This enables a VR user to explore game levels where they assemble various construction components in
accordance with predefined game rules. In timed exercises, this prototype investigated a player's capacity to put
together previously examined construction assemblages. Users are shown in-depth representations of components
that have been prepared at various stages of development. To give higher degrees of authenticity to simulate a
physical construction environment, the virtual construction lab studies novel techniques for BIM object integration
along with scene population, texturing, and lighting to enhance player performance (Anifowose et al., 2022). The
player is allowed to study a pre-assembled wall. Thereafter they are provided with a set of geometric objects which
are replicas of the studied materials. They can create more objects by hand-to-object collision gestures, also known
as object spawning, and object placement features including gentle snap-into-place. Translucent shaders are used
to highlight specific areas of the work to make it simple to finish and maintain the player's motivation. Object
interaction and manipulation techniques from the VR construction lab study are adopted for further development
in this study.
2.5 Interactive Visualization of Building Energy Efficiency
The purpose of this exploratory research is to investigate the use of virtual reality (VR) technology as a platform
for visualizing schematic energy simulations at an entry level. We seek to answer questions such as -
ITcon Vol. 28 (2023), Anifowose et al., pg. 543
• Can VR provide immersive and visual understanding of buildings response to sunlight and heat?
• What best development methods in VR are crucial for visual representation of building energy
usage?
• Can users in VR exhibit understanding of buildings’ heat response based on material change?
EnergySIM is a VR prototype that was developed with the intention of enhancing the audience's knowledge of
building energy simulations and the influence of materials properties on the interior temperature and the annual
energy consumption. This was accomplished by presenting visual outputs of the simulations in the virtual
environment with full building scale to assist users in correlating understanding building response to daylighting
and thermal exchange using a visual approach rather than data. In the last two decades, virtual reality (VR)
technology has evolved in a variety of fields. Users may experience what it's like to be fully immersed in a
simulated version of a real-world setting (Diemer et al., 2015).
3. METHOD
EnergySIM presents pre-simulated building exterior surface sun hour exposure for each of the four seasons (winter,
summer, fall, and spring) calculated based on the number of average sun hours impacted on the building floor,
roof and vertical surfaces throughout the calendar year. In addition, for total building energy consumption, cooling
and heating loads, and interior atmospheric temperature mapping, four pre-simulated energy simulation scenarios
are investigated utilizing single glass, double glazing, concrete, and wood materials in the north wall of the
building. Documentation of preferred interaction techniques is accomplished by facilitating users' visual evaluation
of different construction materials with respect to their ability for thermal insulation or resistance to the heat
transfer (R-value). The EnergySIM prototype went through a lot of different stages of development, each of which
included a different platform. The prototype's prime focus is to include the building energy simulation into a high-
fidelity virtual reality environment while also including simulation outputs that are visually pleasing and simple
to comprehend. The primary structure of the EnergySIM prototype is shown in Figure 1. The subsequent section
will provide an in-depth discussion of each stage in the process.
3.1 Case Study
The Farnsworth House is a renowned architectural landmark designed and built by Ludwig Mies van der Rohe
between the years 1945 and 1951. For the purposes of this research, the Farnsworth House has been used as a case
study in the virtual reality experience as well as the thermal and energy simulation. Considering that its design and
layout were controversial during the time it was being built, the Farnsworth House is a well-known project, not
just among architects and engineers but also among the public. Additionally, it is a symbol of the modernist
movement together with the works of Mies van der Rohe. The walls of the home are almost entirely made of glass,
which has a significant influence on its energy consumption. Our research questions the possibilities of visualizing
such building energy footprints and conveying the information in a visual manner while comparing changes in
wall materials and corresponding energy usage. These are the primary factors that contributed to the decision to
utilize the Farnsworth House as the basis for the EnergySIM prototype. The location of the home is Plano, Illinois,
United States. In Plano, the summers are exceptionally long, warm, humid, and rainy; the winters are freezing,
snowy, and windy; and it is consistently partially overcast throughout the year (Places).
3.2 VR Prototype Development
The EnergySIM prototype was rigorously tested for performance and visual fidelity while also exploring the most
efficient methods to aid ease of entry to future developers without advanced modeling, simulation or coding skills.
In this paper, we document optimized workflows aimed at achieving the best visual fidelity and file integrity for
developers who can apply these methods towards more complex education VR applications. For considerably big
projects, it is important to optimize objects to aid performance (Al-Adhami et al., 2018). In this prototype
development, we highlight optimization techniques for improved game performance on average specification
computers without compromising visual fidelity.
ITcon Vol. 28 (2023), Anifowose et al., pg. 544
3.2.1 Workflow and challenges – Phase 1
The prototype’s primary objective is to visualize how building geometry responds to solar energy. To help design
students understand this, we developed a framework for visualizing 4 simulated seasons (Winter, Spring, Summer,
and Fall). To make users learn better, it is best determined to provide a schematic and more simplistic rather than
precisely accurate real-time data visualization. Object manipulation and game performance were chosen over data
manipulation as tactile feedback is important within virtual environments. The simulation was developed using a
series of modeling, simulation, texturing, lighting, and game development tools which are analyzed below based
on their capabilities.
After careful consideration, we chose Autodesk Revit (Autodesk) as a primary Building Information Modeling
(BIM) tool due to its industry popularity, speed and accuracy of representing building components. SketchUp was
chosen as the next geometry modeling and editing tool. Since this research objective is to enhance visual output
for educational VR applications, we chose Sunhours (Hall, 2022), a plugin as the preferred energy simulation tool.
Several alternate comparisons and daylight analysis in various software and plugins such as Autodesk Insight
(Autodesk, 2022a), Sefaira (Sketchup, 2022), Ecotect (Autodesk, 2022b)were tested rigorously for the most
streamlined workflows while achieving both visual fidelity and speed. Although Autodesk Insight provided great
accuracy, there was no known method of exporting the geometry with the associated visual/texture data. A
significant challenge to VR development is performance, while ensuring that user experience is not diminished by
slow or stuttering frames. It is worth stressing that a file format converter; CAD Exchanger (CADEX, 2022), was
used to retain vertex colors while working across software platforms with results in FIG. 1.
FIG. 1: Visually consistent workflow between Ecotect, CAD exchanger, Rhinoceros and Unity
Amongst several file exchange formats tested including VRML, DWG, CSV, PNG and more, the OBJ, DAE and
FBX provide the best visual geometric consistency towards the best performance. File size was not a significant
factor that contributed to performance however, the number of faces in the geometry directly affected game
performance. We discussed game performance optimization in a later section of this paper also using strategies
from a previous VR game development research (Anifowose et al., 2022). To improve understanding, it is
important to present the energy simulation using the most visually accurate methods outside the simulation
software. Results in FIG. 2 show the most visually appealing workflow for superimposed vertex colors by -
1. Ecotect > VRML > CAD Exchanger > 3DM > Rhinoceros > FBX > Unity.
2. SketchUp + Sunhours > FBX > CAD Exchanger > 3DM > Rhinoceros > FBX > Unity.
Since Ecotect has been discontinued, the SketchUp + Sunhours plugin combination provide the most desired visual
result for daylight analysis. The CAD Exchanger software in 3DM export format provided the best model
translation input and output for visual consistency between both workflows. Even though the fastest workflow is
the direct FBX export from Sketchup to Unity 3D approach, it resulted in more manual work through Substance
Painter. Imported geometry exhibited pixelated surfaces when shader materials are applied in Unity 3D. This
ITcon Vol. 28 (2023), Anifowose et al., pg. 545
breaks user experience within VR due to overlapping pixels causing a potential to increase VR sickness. The
recommended optimized workflow is shown in FIG. 2.
FIG. 2: EnergySIM file exchange recommended optimized workflow.
3.2.2 Visual optimization and Results
The results demonstrate visual consistency throughout the workflow. This was developed further into a second
phase where building energy consumption is visualized via the use of indoor temperature mapping. To retain the
geometry’s best visual appearance, vertex shading strategies were developed via the game engine software with
snippet code shown in FIG. 3. Prior to the development of the vertex shading technique, the application suffered
from poor frames per second (FPS) performance causing discomfort to players due to the numerous rendered faces
and vertices. Unlike surface shading, vertex shading improved the game performance by 45%.
FIG. 3: Shadergraph custom script in Unity for Optimized Vertex Shading
For best results, we selected all nine (9) tools used in the entire process and compared them based on eight (8)
different factors of varying strengths and weaknesses resulting in a 56-box matrix. This comparison matrix shown
in FIG. 4 is generated from weighted factors with ratings between 0 (not applicable) to 3 (most recommended).
Although these software/tools have different functionalities, their overall rating indicates their significance to the
entire development process and results. Following rigorous testing evident in FIG. 5, we suggest the best tools
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ITcon Vol. 28 (2023), Anifowose et al., pg. 546
based on chosen metrics i.e. price, geometry modeling, learning curve, energy simulation, visual data export, file
format compatibility, texture mapping, game development and interaction. This comparison guide is aimed at
helping developers select applications based on their expected development outcome and available resources.
Results may vary in individual cases however, this guide shows our most recommended tool(s) in order of
preference, measured across each metric.
FIG. 4: Software/Tools Comparison Matrix showing recommended features
ITcon Vol. 28 (2023), Anifowose et al., pg. 547
FIG. 5: Result of visually consistent shading through the workflow
3.2.3 Workflow and challenges – Phase 2
To further test the results from Phase 1, we established new objectives to visually represent the embodied energy
within the building using heat transfer coefficients of various materials. When various materials are selected, a
user within the VR environment can see the visual changes in heating and cooling loads based on heat sources (the
sun), lighting sources or aperture/opening sizes based on the insulation material characteristics.
Since there was no direct access to the building document, assumptions were made. The existing space was
assumed to have a single non-reflective glazed exterior wall with an R-value of 0.144 m²K/W (0.82 Ft²·°F·h/BTU)
and a 55% Solar heat gain coefficient (SHGC), a cast in site uninsulated concrete floor with an R-value of 0.132
m²K/W (0.749 Ft²·°F·h/BTU), and a concrete roof with m²K/W (32.337 Ft²·°F·h/BTU) R-value. Users are given
the opportunity to engage with the EnergySIM and change the construction materials and assembly of the north
wall by selecting from among four different types of building materials that each have a unique R-value. One kind
of outside wall glazing has an R-value of 0.0399 m2K/W (0.227 Ft²·°F·h/BTU) and a SHGC of 55%. A pair of
wooden exterior walls, one with an R-value of 1.995 m²K/W (11.329 Ft²·°F·h/BTU) and the other with an R-value
of 4.989 m²K/W (28.329 Fto2F.h/BTU). The final wall assembly consists of an uninsulated concrete wall that is 8
inches thick and has R-value of 0.088 m²K/W (0.499 Ft²·°F·h/BTU).There are a total of five situations based on
the findings of the energy simulations, one of which is the current state (single glazing) and four others involving
different wall assemblies seen in FIG. 6.
These configurations were setup in the energy model and generated in Rhinoceros 3D when the representational
building geometry model was complete. We ensured that the geometrical roles of the EnergyPlus simulation engine
was considered. The EnergySIM prototype uses the simulation engines EnergyPlus and Radiance for the entire
simulation type. The Grasshopper platform, which is a plugin for Rhinoceros 3D that enables algorithmic
modeling, makes it possible for third-party developers to create a broad variety of helpful extensions. The
simulations of the energy usage and customized thermal maps have been carried out with the help of the Ladybug
Tools plugin as seen in FIG. 7, FIG. 8, and FIG. 9. Ladybug's energy simulation is powered by EnergyPlus, while
FIG. 6: Five Wall Material Variations for energy simulations (a) Single Glazing (b) High Performance Glazing
(c) Uninsulated concrete wall (d) Wood Framed Wall R 12 (e) Wood Framed Wall R 28
ITcon Vol. 28 (2023), Anifowose et al., pg. 548
its spatial analysis is a joint effort by the EnergyPlus and Radiance simulation engines. The Ladybug spatial
thermal map simulation combines three spatial thermal map simulation techniques (Arens et al., 2015; Menchaca
Brandan, 2012). Comparing the Ladybug simulation approach to ENVI-met software and field data, this method
has been tested and displays a satisfactory range of consistency (Hongtao & Wenjia, 2018; Ibrahim et al., 2020).
EnergySIM provided simulations for various scenarios shown.
FIG. 7: Summer Box Map – (A) Single Glazing (B) Double Glazing (c) Concrete (D) Wood R12 (E) Wood R28
FIG. 8: Winter Box Map – (A) Single Glazing (B) Double Glazing (c) Concrete (D) Wood R12 (E) Wood R28
FIG. 9: Indoor temperature box map script for different seasons.
Total annual building energy use is calculated using data from the University of Illinois-Willard Airport
EnergyPlus weather station, one of the closest to the site. According to the weather data collected by EnergyPlus,
the hottest and coldest days of the year occur during the summer and winter simulation periods, respectively
(EnergyPlus). Time in the summer is on the 13th of July at 3:00 PM, while time in the winter is on the 3rd of
February at 7:00 AM. The interior wall temperatures, which are the wall surfaces of the interior layer, have been
represented by simple single surfaces that overlay the building model. The Vertical interior temperature maps are
ITcon Vol. 28 (2023), Anifowose et al., pg. 549
formed by stacking 450 sensors in a vertical orientation to create a single surface. The boxes interior temperature
maps are a collection of 360 sensors uniformly arranged around the buildings, with one box representing each
sensor. Several other kinds of charts and graphs are used to illustrate the annual cooling and heating loads, as well
as the total annual energy usage.
3.2.4 Scene Exploration and Interactions
EnergySIM is developed to enable more than one person co-experience the simulation results: a typical student
and professor classroom scenario. This prototype is designed putting accessibility into consideration therefore
allowing users to complete the experience in either sitting or standing positions. Although both hands can be used,
it can equally be completed with only a single hand. For the Users, we segmented the VR learning experience into
three strategies as shown below -
1. Exploration - A 1:1 full scale Farnsworth House model. This is provided for exploration with super-
imposed simulation results from the 4 seasons and the indoor temperature maps perceived in full scale in
its original material configuration (glazing, steel, concrete). This section enables users to familiarize
themselves with the building in its full-scale form and understand how the components are geometrically
related i.e. floor, wall/glazing, ceiling/roof. This approach provided realism and spatial perception of
building scale towards the experience.
2. Miniature Model manipulation - A collection of 1:25 scale handy miniature models, allowing virtual
manipulation of the simulations with varying seasons. This enables users to study the geometric form and
its relationship to solar heat gain at a granular level. This approach provided grab and translation (moving
7 rotation) techniques thereby increasing tactile feedback, and perception of scale at object level, all which
are essential factors which were previously documented to contribute to design learning (Anifowose et
al., 2022).
3. Menu-driven Material Configuration - A non-movable 1:10 scale Farnsworth House is provided with a
corresponding user interface. The interaction level features users configuring various types of materials
showcasing building heating and cooling load changes based on the selected materials’ R-values in FIG.
10. Users are asked to manipulate the values in the menu based on input using a pair of VR controllers.
Depending on the combination or selections (season and construction material), the corresponding pre-
simulated result is displayed in the 1:10 scale model alongside corresponding temperature scale.
The material comparison charts are provided for improved user understanding. When a user selects a specific
material, the corresponding heatmap is loaded and every other heatmap is temporarily destroyed. This aimed to
provide deep visual understanding of the building’s specific heating or cooling state based on the selected material.
The average internal temperature is also displayed in a corresponding vertical map on the side of the building
FIG. 10: In-game image showing menu and material comparison charts
ITcon Vol. 28 (2023), Anifowose et al., pg. 550
which gives an idea of how hot or cold an area is. As show in the image, areas around the glazing appear warmer
than the innermost sections.
These three strategies allow a wholistic experience for a wide range of users who may approach the experience
with various learning strategies. Although this study did not compare which strategy provided users with the
highest learning impact, that question is currently being investigated in another research.
3.2.5 Performance Optimization and Improved Results
To ensure consistent game performance and frames per second (FPS) delivery, game optimization strategies were
employed by merging meshes and materials to reduce draw calls on hardware resources. Plugins used to achieve
these include the Mesh Combiner Script and Pro Materials Combiner. The best strategy to avoid errors require
placing and retain geometry integrity require placing sub-meshes under the same parents before a merge command
is executed. Turning off cast shadows if hardware resource is limited and assigning blend probes for light probes
is equally proven to be best practice. This approach is confirmed to drastically reduce computation time for mesh
combinations.
3.3 Demonstration results
The overall Virtual Reality experience was developed using the Oculus XR framework inside Unity (Unity, 2021)
and tested using the Meta Quest 2 VR Headset. Feedback received from trial runs with a high school education
content administrator and other researchers revealed that the prototype provides an entry level opportunity for
students to learn about the fundamentals of building energy simulation in VR environment. A demonstration of
the prototype is available in this link https://youtu.be/nV9YBI1-qYM and as shown in FIG. 12.
FIG. 11: Chart showing differences in material R-value
ITcon Vol. 28 (2023), Anifowose et al., pg. 551
4. DISCUSSION
4.1 Virtual Reality Validation & Future Works
This study demonstrated the potential of an Energy Simulation VR prototype development towards higher visual
fidelity and improved learning outcomes. The system provides an interactive environment for learning how the
Farnsworth House (case study), responds to daylighting and energy consumption across various seasons and four
material scenarios: single glazing, double glazing, concrete walls, and wood construction for interior atmospheric
temperature mapping. In this study, rigorously tested workflows are documented with a focus on the improvement
of VR game performance, interaction of users and increased visual fidelity which are three key factors that are
responsible for positive knowledge retention in users. The most optimized development workflows are shown and
the demonstration impact on users has clearly answered the questions, indicating that user understanding is
improved by the documented methods of interaction and miniature model manipulation. Users also showed
improved understanding of the varying requirements of heating and cooling loads based on material changes from
glazing, to concrete and then wood with varying R-values.
Although the development or impact of in-game audio narration is not a key component of this study, it is worthy
to mention that an audio narrative of the game experience was included to allow users have preliminary
understanding of the building’s background, history, needs and required tasks in the VR experience. The
EnergySIM introduction level welcomes the students by providing an audio narration of the history of the
Farnsworth House and the building materials/features vis-à-vis heat and energy consumption and requirements.
The audio component played a role in helping users with varying preferences for learning touchpoints, adjust to a
virtual learning environment devoid of a physical instructor.
This study combined geometry optimization techniques, menu driven interactions and miniature model
manipulation, while at the same time, testing user understanding and knowledge retention regarding building
energy usage. Although not gamified, the future objective is to make the prototype a game experience with a goal
of impacting learning in high school students who have interests in building design courses at university level. The
EnergySIM VR prototype pushes the boundaries of visual fidelity in simulations showing recommended tools and
methods for best visual impact towards learning. The provided workflow is optimized for educational VR
application developers, instructors, and design students. EnergySIM achieved the simplification of teaching
advanced level building energy response, down to an enjoyable, visual yet impactful rudimentary level.
4.2 Limitations of Study
As seen in (Sidani et al., 2021), Most BIM-to-VR applications are composed of four layers; a BIM tool, a game
engine, visual enhancement module and a non-geometric database component. This study did not take into
cognizance, the possibility of exporting data associated with the geometries which is the 4th component. If
researchers plan to include data visualization in their workflow, they should be aware that optimizing game
performance may require additional strategies. We hypothesize that the inclusion of real-time data visualization
may provide deeper immersion however, developers can expect longer development times and, significant drop in
performance based on the high amount of computation required per changed variable such as material or building
FIG. 12: Photographs from demonstration and feedback session
ITcon Vol. 28 (2023), Anifowose et al., pg. 552
orientation relative to the sun’s direction. It must be noted that real-time data visualization was not part of this
research’s objectives. It is also worthy of mention that none of the simulation texturing was baked since they are
dynamic geometric components in the scenes (such as concrete wall, glass, and dry wall). Only static components
such as the main building and surrounding environments were texture baked (using Substance Painter). All
dynamic components and simulations have shaded vertices which received real-time lighting, shading and
reflection.
4.3 Funding Sources
This research is partially funded by the US National Science Foundation (NSF) grant (CBET, 2048093). The
opinions, findings, and conclusions, or recommendations expressed are those of the author(s) and do not
necessarily reflect the views of the National Science Foundation.
5. CONCLUSION
This research presents EnergySIM, a novel virtual reality (VR) development workflow which is designed to
facilitate the understanding of building energy simulation principles. The complexity of this subject poses a huge
challenge for learners which the proposed EnergySIM addresses by offering an immersive and interactive VR
experience while also demonstrating a step-by-step approach for development. This paper highlights the need for
an optimized workflow and an approach for developers and instructors who seek to simplify complex subjects
using VR. The comparison of various software provides easy understanding of expected results depending on the
chosen development pathway. Performance optimization techniques are provided in this paper for recommended
vertex shading, lighting, and texturing approaches.
Feedback from trials indicates that EnergySIM opens new possibilities for learners in an entry-level platform. This
research contributes to the advancement of educational VR applications, paving way for more intuitive and
practical applications and approaches to studying the impact of building geometry and the choice of design
materials on solar heat gains and energy efficiency or usage.
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