Integrating performance-based design in beginning ...

Integrating performance-based design in beginning interior design education: an interactive dialog between the built environment and its context Qun Zuo, Faculty of Interior Design, Department of Human Environmental Studies, USA Wesley Leonard, College of Health Professions, USA Eileen E. MaloneBeach, Department of Human Environmental Studies, Central Michigan University, Mount Pleasant, MI 48859, USA This paper presents a new paradigm in interior design education in which building performance simulation was employed for decision making and design generation. Digital technology was intermixed with conventional paper-based media in the design process to explore formal, spatial and passive solar energy solutions. The intention of the study was to re-discover the value of computers in assisting design thinking and improving effective learning. The results indicated the Performance-Based Design approach resulted in an early awareness of sustainable energy for beginning interior design students. Further, it enhanced understanding of the mutual relationship between interior and exterior and between the built and natural environment. This paper acknowledged the achievements as well as limitations and future directions for the integration of Performance-Based Design into interior design curriculum. Ó 2009 Elsevier Ltd. All rights reserved. Keywords: performance-based design, interior design, design education, computer aided design, design process

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merging interest in sustainable built environment has been changing the way that architects, interior designers, and engineers design buildings. Building performance is no longer a post-evaluation after the design is ‘complete’ (Burger, 2008). Instead, its criteria are digitally simulated and analyzed during the design process and are used as guiding design principles against which building form is evaluated and modified (Fasoulaki, 2008). This integrated approach has altered the traditional process of conventional design and has the potential to affect building energy use, improve spatial experience, and influence aesthetic decisions (Burger, 2008). Corresponding author: Qun Zuo juliezuo@hotmail. com

A new framework for design pedagogy must be responsive to the emerging approach in which performance-based design (PBD) is integrated as an effective process for design decision making. Various educational agendas have been www.elsevier.com/locate/destud 0142-694X $ - see front matter Design Studies 31 (2010) 268e287 doi:10.1016/j.destud.2009.12.002 Ó 2009 Elsevier Ltd. All rights reserved.

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developed in architecture and engineering disciplines, especially in many graduate programs, to integrate digital building performance tools into the curricula (Oxman, 2008). However, the teaching of interior design as a discipline has lagged in this effort. The paradigm of design in many studios is still strongly predicated upon visual reasoning solely (Oxman, 2008). Thus, some aspects of sustainability, such as passive solar energy use, cannot be taught in-depth. The old ways of delivering digital techniques emphasize the representation aspects of Computer Aided Design (CAD) (Basa & Senyapth, 2005x ), but lack exposure to its simulation and analytical capabilities for assisting design generation. It is essential to re-orient our approach within interior design education, especially in the undergraduate curriculum, to open up new territories for formal, spatial and energy use exploration. This paper proposes a new teaching pedagogy in beginning interior design courses, which employs performance simulation and analysis as an impetus for design decision making. A residential design project with the scope of achieving optimal harmony between building form and its natural environment was carried out in a studio and an advanced CAD course for study. The pedagogy was different from the old delivery in five aspects: first, teaching content: sustainable design principles of using passive solar energy was integrated to better understand the mutual relationship between the interior and exterior conditions of buildings, and between the built and natural environments; second, design tools: digital and non-digital media were intermixed in the design process; third, design process: building performance analysis was applied in the early design stage; fourth, teaching pedagogy: a more active teaching and learning mode was realized through the use of digital simulation tools; and fifth, class organization: the studio and the CAD course worked jointly on the project by sharing the same site and design resources. This paper reviews the theoretical framework and precedence of the study before outlining the implementation, assessment and findings. Limitations and future directions are also described in order to improve this prototype for better application in interior design education.

1

Developments in design practice

A number of recent developments in design practice now impinge directly upon education.

1.1

Sustainability

The exploration of the built environment in relation to its social and natural context has been a continuous theme in the history of architecture and interior design. Contemporary design theory promotes an environmentally sustainable approach or Green Design to address the problems in which issues of the environment are interrelated with human development and progress. The 1987 conference of the World Commission on Environment and Development (WCED) defined such an approach as ‘meeting the needs of the present

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without compromising the ability of future generations to meet their own needs’. In the last decade, developing more environmentally benign products, processes and buildings became one of the fastest growing segments of the building industry (Hendrickson, Conway-Schempf, Lave, & McMichael, 2000). The Leadership in Energy and Environmental Design (LEED) Green Building Rating System includes five environmental topics: site, water, energy, materials and resources, and indoor environmental quality. While all of these aspects are critical, the U.S. Environmental Protection Agency (EPA) identified energy as the most important component (Kibert, 2005). The teaching and practice of sustainability is not a trend but has become a necessity in the field of design. Many successful academic addenda have integrated sustainable content into higher level undergraduate courses in interior design education. Numerous good examples of course activities can be found at: http://www.idec.org/greendesign/home.html. However, sustainable materials and indoor environmental quality have been emphasized, whereas sustainable energy has been given much less attention within the profession (Kang, Kang, & Barnes, 2009).

1.2

Whole-building design

To better address the demand of sustainability, a Whole-Building Design approach emerged with the goal of creating high-performance buildings which can reduce energy demands and minimize environmental impact. Users’ interactions with the built environment are defined as a set of measurable building performance criteria, which can be categorized at three levels: 1) health, safety and security performance; 2) functional, efficiency and work performance; 3) psychological, social, cultural and aesthetic performance (Preiser & Vischer, 2004). The Whole-Building Design approach differs from the traditional design and construction method, as the physical aspects of building performance, such as siting and orientation, building form and structure, the mechanical system, interior space planning, material and furnishing selections, lighting, along with other building systems and components are integrated as a whole in the design process. Such a holistic design approach depends on the collaboration and on-going communication among the project team members, including architects, engineers, owners, contractors, interior designers and energy specialists. To optimize the overall building performance, the team must make decisions together in all stages of a project, starting with establishing performance goals in the early design phases (Whole building design, 2009). Thus, an effective approach to simulate and evaluate building assets in an integrated view is critical to the Whole-Building Design approach. Interior designers should no longer receive a plan from the architect to perform space planning, material specification, furniture selection, and code and regulation applications. Instead, they are important co-players in the Whole-Building Design process and should be contracted at the onset of a project (Frances, 2009). Their responsibilities within the team include but are not

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limited to adjusting space planning and furnishing positions according to HVAC zones, mechanical rooms, equipment, ductwork and piping; selecting colors, finishes, lamps, and window operation and treatment relative to energy efficiency; and coordinating interior components to passive solar energy and other sustainable approaches.

1.3

Performance-based design (PBD)

While the need for creating environmentally attuned buildings is one of the strongest motivating forces of building performance simulation, the advancement in computational technology offers the tools to maneuver building assets in the digital domain. From its inception, the idea that computers have the potential to support design activities, two directions of applying computation in design have been used: one is its visualization and representation aspect, which includes two-dimensional drafting and three-dimensional visualization of forms and spaces; the other is its calculation and simulation aspect, which allows quantitative or qualitative evaluations of building performance (Fasoulaki, 2008). The distinction between the two is significant. Computer generated presentations have been basically founded on imitating paper-based design, while digital calculation and simulation have introduced a new body of knowledge, theories, methods, and processes (Oxman, 2008). Since the late 1960s and early 1970s, a variety of pioneering computational generation and simulation models have been developed or tested. One such model, the performance model (Oxman, 2008) or performance-based design (PBD), utilizes optimization and simulation algorithms to evaluate building form against performance criteria (Fasoulaki, 2008). Computational tools and methods made it possible to reveal an integrated view of the contemporary built environment (Brahme, Mahdavi, Lam, & Gupta, 2001). It enabled the exploration of complex forms, comprehensive fabrication and manufacturing processes, and the optimization of the building components and systems (Kolarevis & Malkawi, 2005). Currently, architects and engineers have been at the forefront of PBD development. As a contrast, there has been little effort to employ PBD in interior design practice. Most teaching contents on sustainability have been tailored for seminars or studios using conventional media in interior design education (Bourque, DuvalleHarden, Fowles, Ginthner, Jones, & Truelove, 2003). Building performance simulation has been either missed, or if included, not applied at its full capacity for decision making as is the case for Kim’s (2008) approaches to teaching sustainability. In order to coordinate the interior components for optimized sustainable solutions, interior designers should be actively involved in the Whole-Building Design practice and assume a collaborative role in the integration of PBD in the design process.

1.4

Transforming design tools and process

The fact that the advancement of digital technologies has been consistently changing the design process does not expel conventional hand skills from

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design practice and education. On the contrary, designers have recognized the complementary nature of each medium and recommended a ‘smarter’ practice of intermixing digital and non-digital tools (Mueller, 2006). The activities of design thinking strongly based on visual reasoning through paper-based media, such as sketching and physical modeling, are referred to as ‘reflection in action’ (Scho¨n & Wiggins, 1988). Architects and designers have been depending on paper-based methods for conceptual and explorative processes since the Renaissance. Until recently, design professionals were still of firm belief that hand techniques are faster and more intuitive in the early design phases, where information is uncertain and imprecise (Basa & Senyapth, 2005 x ). Numerous studies have indicated that this paradigm has been applied universally in architectural and design education as a dominant model for ages (Oxman, 2008). Often criticized as an imitation of paper-based media, computer aided presentations have been identified with problems of loss of identity, lack of authenticity and demands of proficiency (Basa & Senyapth, 2005x ). However, its efficiency in both time and cost for design documentation and visualization has made it well adapted into design practice and education. More promisingly, the fast development of PBD has altered the traditional design process and sequence by enhancing design solutions with building performative evaluation and verification (Oxman, 2008). The amount of data and the speed that computers can handle far exceeds the capabilities of hand techniques. The more comprehensive the building condition and its context, the stronger the advantages of a PBD approach. Researchers predict that the interplay of digital and non-digital methods will be a persistent feature of design activities for the perceivable future (Mueller, 2006). The theory is that the intermixed application of real and virtual objects can be a prime source of exchanging information, enhancing understanding, and inspiring new ideas (Dorta, Pe´rez, & Lesage, 2008). The pioneering masterpieces by Frank O. Gehry, Zaha Hadid, Peter Eisenman and many more architects are living examples of the integrated approach at work. Similar investigations have taken place at MIT, Carnegie Mellon, UCLA, Harvard, Pennsylvania State University, University of Michigan, and elsewhere around the world (Oxman, 2008). These recent developments and emerging tools in design practice pose new demands on educators to re-investigate the value of digital technologies in contemporary interior design education. Building performance simulation, in particular, has offered interior designers an opportunity and challenge in their sustainable practice. This research was an effort to respond to the demand of integrating PBD into interior design curriculum. The study focused on spatial relationship, orientation, and daylighting simulation, since these aspects are

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fundamental for beginning interior design students. The following questions are examined in this paper: Does the nature of PBD affect the design process to the extent that interior design education must accommodate it as a new process and method in the curriculum? How effective are the PBD versus hand skills in facilitating the student learning experience? Does PBD effectively impact student’s design outcomes and performance?

2

Method

The study was carried out on a dwelling design project in two interior design courses through two consecutive semesters in 2008 2009. One course was the second interior design studio in the program which focused on residential design. The other, advanced CAD, taught three-dimensional modeling and visualization techniques. Each semester, the two courses paired up for two sessions. Fifty-five students enrolled in the four sessions and 51 completed the survey, which included 10 in session 1(studio, fall semester), 16 in session 2 (CAD course, fall semester), 16 in session 3 (studio, spring semester), and 9 in session 4 (CAD course, spring semester). All students were sophomore interior design majors. They shared the same residential site and were required to employ both hand and computer techniques for design generation. A panel of four evaluators was invited to jury students’ final presentations in all four sessions. All jury members have had teaching and/or industrial experience in architecture and/or interior design. Three out of four were instructors in the program and had been invited to critique students’ work of the same project in previous semesters. Half of the jury members had working knowledge of at least one of the computer programs used in the project. The study investigated the integration of PBD in the design process in interior design education. It differs from the old delivery mode in five key aspects: the establishment of new design knowledge as the core content, the integration of digital performance simulation as an analysis tool, the changes in design process as building performance was involved in the early design stage, the renovation on teaching pedagogy, and the new way of organizing classes.

2.1

New design knowledge

The given site of the design project was a waterfront dwelling village located on the east shore of a lake in central Michigan in the U.S. The topography was a hillside sloping downhill toward the lake. Design problems included dwelling form generation, interior space planning, landscape design, as well as the considerations to neighborhood context, topography, climate, solar orientation, prevailing winds and views. Among the many factors that students must coordinate, daylighting, spatial relationship and views were selected for performance simulation and were employed as the guiding design principles for form generation. Criteria such as daylight distribution, orientation, glazing to wall ratio, window placement and window treatment were used to maximize natural lighting and reduce glare. The intentions of this project

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were to deliver new design knowledge to beginning interior design students by 1) introducing passive solar energy as one of the sustainable design principles; 2) integrating PBD to enhance their understanding to the mutual relationship between the interior and exterior conditions, and between the built and natural environments.

2.2

New design media

In order to evaluate whether the use of PBD versus conventional paper-based media would benefit student learning and outcomes, both hand and digital techniques were employed in the design process. Besides the typical hand sketching and physical modeling supplies, two software programs were used for digital modeling, rendering, and simulation: SketchUp (http://sketchup.google.com) was selected for digital modeling due to its intuitive and efficient nature. Novice users can learn to use SketchUp quickly. Compared to traditional CAD modeling software, its interface and operation are much simpler and more straightforward, which speeds up the modeling process. Thus, many users claim SketchUp is analogous to physical modeling and consider it as an excellent tool for exploring schematic design ideas. In addition, SketchUp files can be exported to traditional CAD programs for final documentation, photorealistic rendering, and performative simulation. All participants in this study had had working knowledge of the program prior to the project. Autodesk VIZ (a program similar to Autodesk 3ds Max), which is an advanced 3D modeling program, was used to perform computer rendering and the simulation of spatial relationship, daylighting and views. It was the major software being taught in the advanced CAD course. Students were able to set up multiple cameras in and outside of each dwelling in the virtual domain to explore what was visible from where. Lighting simulation and analyses were presented in both vivid photorealistic quality and pseudo color mode, which offered direct visual information to students. Participants in the project either had had experience with VIZ or were in the learning process, but none had used the daylight simulation feature prior to the project. Since colors, materials, and furnishing details could distract viewers’ attention and dramatically slow computer generation and calculation, a monochromatic color scheme (white) and generic furniture were used during daylighting simulation and analysis in the early design stages. Nevertheless, photorealistic quality renderings were required as the final products in the CAD course.

2.3

Changes in design processes

The old design workflow of the studio had followed the ‘prescriptive’ model: the abstract hand sketches and the malleable physical study models were used to explore design ideas in the initial conceptualization phase; then they were transformed into a set of digital plans, sections and elevations in the design

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Figure 1 Conventional interior design studio work flow derived

from

Mueller’s

(2006) Design Work Flow

development stage; in the end, the final design solutions were executed as accurate CAD documents and precise physical models for presentation purposes. Even in a more advanced digital application in higher level interior design studios, orthographic drawings were often used to generate three-dimensional computer models which could either support plans, sections and elevations or offer digital perspective imaging as manual renderings do. The digital data merely recorded the design changes and final results. There were no design activities immediately directed at the digital media. The workflow is illustrated in Figure 1, which is derived from Mueller’s (2006) Design Work Flow. The disconnection between design thinking and digital tools was also true in the past CAD classes. Students were provided with a set of standard floor plans and elevations, from which they were supposed to reconstruct the building on the monitor in order to practice computer techniques. Students tended to get bored by the tedious procedures. Some students were not able to see the value of daylight simulation, since a few standard fake light objects could make the imaging look beautiful and refined with less effort. Such a teaching approach failed to reveal the full capacity of digital technologies as design tools. This study tried to create a much more active and engaging learning mode. Participants worked interactively on paper, with physical and virtual models, through which to re-discover the value of digital three-dimensional data for decision making. The assistance that digital technologies provided was two fold, in both formal and spatial exploration, which was visual reasoning, and building performance simulation, which was algorithm based. This added a dynamic loop in the early design process of evaluating building performative factors against building form, which could augment the diversity and depth of design thinking. The new workflow is shown in Figure 2, which is developed from Mueller’s (2006) Design Work Flow.

2.4

New teaching pedagogy

In the previous studio, one of the major objectives was to convey design intention, especially formal and spatial generation, through visual reasoning. As a result, the use of paper-based media was emphasized for its effectiveness to explore fundamental design principles for beginning designs students. However, sketches and scaled mockups were challenged to present spatial

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Figure 2 Performance-based Design Work Flow developed from

Mueller’s

(2006)

Design Work Flow

relationship at various scales and viewing angles. Although full-scale physical models could solve the problem, it was not practical or meaningful for constructing a dwelling site at its real size. The teaching and learning experience could be more challenging when daylighting was involved as one of the key factors for decision making. Visualizing the solution through physical models and manual calculation would largely depend on the student’s ability to imagine both his/her own design outcome and the instructor’s feedback. It was extremely difficult to get objectively reliable perceptions in the communication between the student and the instructor (Feng, 2003). The integration of PBD offered an opportunity to overcome the limitations of conventional design media as well as to fill the gaps in studio communication. The teaching and learning experience was improved by a test-and-run approach. The same was true in the CAD course in which students were able to apply new computer techniques directly to assist design decision making in an on-going project. The role of the instructors was even more critical in the new approach. They not only worked on a one-to-one basis with each student for design issues but also technically supported computer application techniques and operational questions. In addition, they monitored the construction and updating of the dwelling village in both physical and digital model formats, which required fluency in both digital and non-digital tools. Their responsibilities shifted from tutors or supervisors to co-explorers or project directors. More active and experiential learning activities were a strong contrast to the original passive teaching mode.

2.5

Changes in class organization

This study tied the studio and the CAD sessions in each semester into one through sharing the same project site and design resources. The studio sessions had 6 weeks, 5 contact hours per week, and a total of 30 contact hours; the CAD sessions had 7 weeks, 4 contact hours per week, and a total of 28 contact hours. The CAD sessions were started one week earlier in order to run parallel

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with the studio sessions in the design development process. The schedule of each course is attached in Appendix A. Each student was assigned a slot in the dwelling village by lottery. Both a physical and a digital model of the residential site were available to two sessions. Students in the studio session launched their design with physical study models, which then was converted into SketchUp models. In the mean time, students in the CAD session began their design directly in SketchUp, from which, floor plans and elevations were plotted as hard copies and then attached to foam core to make the physical study models. Instructors evaluated the physical and the SketchUp study models and offered feedback to students for design revisions. Afterwards, the schematic designs were imported into the digital site. Spatial and daylighting simulation and analysis were executed in VIZ. Further revisions and alternative solutions were tested and the results were available almost immediately on the computers. For example, the amount of daylight entered a space and the view to the exterior changed right away if the shape, location, or dimension of a window was modified (Figure 3). The VIZ site model was updated promptly to keep everyone on the same page. Students presented their work to the panel of juries in both physical and digital formats, which were set up side-by-side for the convenience of the jury and audience. Each student was required to produce a walk-through animation in the format of monochromatic color scheme and generic furnishing and to use it as evidence for explaining the design generation. The major differences of the presentation materials between each paired sessions were 1) the scaled mockups from the studio session were of fine quality, whereas the ones from the CAD session were less detailed since they were constructed by exporting the digital plans and elevations as templates which then were attached to foam core boards; 2) Students in the CAD session were also asked to turn in photorealistic renderings as the proof of mastering advanced computer presentation techniques (Figure 4).

Figure 3 Students explored interior spatial and daylighting simulation using Autodesk VIZ (a, b) Changing window configurations with generic furniture and materials; (c) Final solution with photorealistic interior composition, colors, and materials

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Figure 4 Students practiced photorealistic rendering techniques using Autodesk VIZ (a, b) Exploring day and night light conditions

3

Instruments

To observe the effectiveness of PBD on students’ performance, data was collected on comparison of digital and non-digital media by using four methods: 1) observing students’ work process, 2) having participants complete questionnaires after their final presentation (see Appendix B for the questionnaire), 3) conducting informal interviews to each participant at the end of the desk critique each week, and 4) having jury members evaluate students work (see Appendix C for evaluation criteria). The questionnaire was inspired by Dorta et al.’s (2008) study on the Hybrid Ideation Space (HIS) and Day and Rahman’s (2006) study on participatory design, which either integrated or compared digital technology with analog tools in design process. The resulting questionnaire asked the participants to evaluate nine dimensions of the visualization and simulation capabilities of both hand and digital modeling approaches using a 10-point scale, in which 1 was the lowest and 10 was the highest. In addition, open-ended questions were included to reveal the patterns of students’ learning experience as well as to suggest directions for future teaching. The evaluation of students’ work by the jury included four dimensions, which ranged from aesthetical, functional, and environmental to psychological aspects. A 10-point scale was also used for evaluation, with 1 as the lowest and 10 as the highest.

4

Results

Most participants were able to work easily with both hand and digital techniques. Only one participant experienced difficulty transitioning to a digital model. For participants in the studio, it took less than one class period to transform the physical study model into a SketchUp model. Many found that SketchUp was much less forgiving than a physical mockup. Since computer simulations are more accurate than physical models, almost every participant identified new problems during the process of digital modeling. Interestingly,

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Figure 5 Daylight were visualized in both photorealistic and pseudo color formats using Autodesk VIZ (a, b, c and d) Above: Human perception renderings of the simulated interior daylight conditions for the different times of the day; Below: Pseudo color renderings of the simulated interior daylight conditions for the different times of the day

the participants in the CAD courses claimed that SketchUp was much less accurate than VIZ. Participants found SketchUp, which is a free consumer tool, was easier to use for exploring conceptual ideas in 3D, while VIZ, as a complex professional tool, was more difficult for free form modeling or revisions. Most of the participants in the studio sessions could more easily visualize issues that the instructors had pointed out in their physical study models after they saw their work in the digital format. They alternated between physical and digital models to refine their designs. Quite a few of them requested at least one extra meeting with the instructors to discuss their design in the virtual format. In contrast, participants in the CAD classes made almost all revisions directly on the computer e either in SketchUp or VIZ models. A few participants claimed that the physical models gave them a more tangible feel for the volumes and dimensions than the digital models, which were expressed as minor changes in their design solutions. Overall, students in studio sessions were more open to modifications than the ones in the CAD sessions. According to the feedback from participants during their desk critique, the tangible feel of paper and boards was much less intimidating than the finished quality caused by the inherent precision and details associated with computers. All four sessions experienced some difficulty when importing SketchUp models into VIZ due to compatibility issues between the two programs. Some participants had difficulty understanding the pseudo color image of the lighting simulation, which instead of visualizing the lighting condition in

Figure 6 Screen shots of a walk-through animation of a house; lighting condition is changing through the day

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Figure 7 Daylight simulation of the entire village site using Autodesk VIZ

photorealistic effects, uses a few colors to illustrate the range of light levels from darkest to brightest. After examining the image for a few minutes, all were able to ‘read’ and understand it (Figure 5). In general, most participants agreed that the multi-view (static, walk-through and panoramic views in and out of each dwelling and fly-through of the entire site) and daylight simulation capabilities were most helpful in identifying better solutions for orientation, building shape, space planning, glazing to wall ratio and solar shading (Figures 6 and 7). We found students enjoyed interacting with digital media. Almost everyone was adding more and more cameras to the scenes in VIZ so they could experience the form and space from more viewing angles, scales, and contexts (Figures 8 and 9).

Figure 8 Multi-views of the simulation model

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Figure 9 Multi-views of the simulated space

Two observations from all four sessions are of special note: 1) the participants confirmed that they used the computer simulation to support their design thinking and not to create digital representations of what they had designed through paper-based media; 2) The studio sessions used the CAD software according to the workflow for supporting the design process; the CAD sessions employed digital technologies for both design thinking and final presentation. Out of 51 participants, only one student decided to work on her design mostly in paper-based format. This student had very strong hand skills in rendering and sketching. She was also strong in conceptualization and form generation. Her work stood out in terms of creativity, formal quality and originality; however, her solutions for solar control and adherence to building codes were less

Figure 10 Comparing the effectiveness of physical vs. digital modeling

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successfully executed when compared to projects that utilized computer modeling. In a way, this student’s design was a perfect counter-example.

4.1

Physical vs. digital media

In terms of the nine-point question related to comparing physical modeling with digital media, the participants in all four sessions gave high ratings to digital media (Figure 10). The overall statistical difference was significant. The difference between each pair of questions was also significant. Participants gave the highest rating to (q7): ‘Ease of visualizing daylight in and out of your house’. High ratings were also given to (q8): ‘Ease of manipulating and modifying your design’. It is worth noting that the difference in scores between physical and digital tools was very close for (q5): ‘Ease of visualizing the orientation of your house in site’. The logical explanation for this is that participants can easily locate their house orientations with an overall sight of the village site in a physical mockup, even though the digital mockup provides more viewing angles, which include a bird’s eye view of the whole site and looking at the neighborhood from any of the houses on the site.

4.2

Open-ended questions

A brief summary of the participants’ feedback to the open-ended questions (Tables 1 and 2) demonstrates the success of the study in a number of ways. The positive feedback to the effectiveness and efficiency of the digital tools rated the highest (99), in which the simulation of daylight, building form, views Table 1 Advantages and challenges of using physical modeling tools

Respondents The advantages of using physical modeling identified by participants Effectiveness & efficiency to assist design thinking 1. Gives the opportunity for a hands-on experience trying ideas 2. Helps to understand the form and space of your building better 3. Helps to see window and door openings and how they relate to each room from the outside 4. Tangible; can hold the model and easily move it around as needed

39 11 12 9 4

Identity of designer 5. Ability to add unique or artistic touches

3 3

Interests & satisfaction of participants 6. Finished model is visually appealing; it was amazing and worth all the time

2 2

The challenges of using physical modeling identified by participants Effectiveness & efficiency to assist design thinking 1. Difficult to make changes or fix mistakes 2. Foam core was very hard to work with. Lots of bloody fingers, very stressful on the eyes, and ‘I got sore fingers.’ 3. You are limited by your modeling techniques to express ideas 4. Less accurate and greater chance of mistakes 5. Time consuming 6. Very expensive 7. Difficult to manipulate or visualize design ideas 8. ‘X-acto knives are dangerous!’

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Table 2 Advantages, challenges, and suggestions of using digital tools

Respondents The advantages of using digital tools identified by participants Effectiveness & efficiency to assist design thinking 1. Lighting changes are visible; easy to see how orientation impacts the interior and how light interacts with the space 2. Great to identify problems of lighting, window placement, clearances, and shapes 3. Digital model was very helpful in seeing the site as a whole and how the neighbors will affect my views 4. Very useful to see and manipulate 3D form (entry, paths through the space, etc.) 5. SketchUp is easy to use for space planning and form generation 6. VIZ helped to make the project look more realistic 7. VIZ can visualize unique walls and details 8. Easier to visualize than on paper 9. If you can navigate through, it is easier to brain storm and try ideas 10. Allowed me to have another medium to express design ideas 11. VIZ is a simple program once you learn it 12. It can put you in the space 13. Switching views is very easy 14. More options 15. Very detailed 16. Quicker Interests & satisfaction of participants 17. Lighting design can be very interesting Challenges of using digital tools identified by participants Effectiveness & efficiency to assist design thinking 1. Need to be very knowledgeable of the program to use VIZ to its full advantage; If not familiar with the program, it can be difficult and cause problems; VIZ is too difficult to learn well in just one semester 2. Overwhelming amount of features and tools to use in VIZ; it’s difficult to express what you imagine in your head 3. Once walls and objects are in place in VIZ, it is difficult to change them unlike drawing by hand 4. Using VIZ is time consuming 5. If too much is added in a VIZ scene, it’s hard to quickly move through the space or render the camera views 6. VIZ is sometimes confusing or moves too fast 7. VIZ program shut down often 8. VIZ is slower on modeling than SketchUp or hand modeling 9. It’s much easier to build walls in SketchUp than in VIZ 10. SketchUp does not seem as accurate 11. The non-realistic appearance of SketchUp can be distracting to the overall aesthetic quality of a building/object 12. Converting models from SketchUp to VIZ was very difficult

99 17 15 12 10 9 8 3 5 1 2 1 3 2 2 4 5 1 1

59 12

8 5 6 4 2 1 5 4 4 3 5

Identity of designer 13. Everyone’s designs were presented in the same ‘format’; difficult to get a personalized design

1 1

Suggestions to future use of digital tools 1. Increase critique time with students in digital format

5 5

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Figure 11 Students at the final presentation using paper-based media and physical models

and site were indicated as being the most helpful in the design process (54). On the other hand, the challenges of digital tools identified by the participants ranked the second highest (59). Students experienced the most frustration with the sharp learning curve of VIZ (43). The results also indicate that physical modeling, computer modeling and digital simulation were all effective to assist design thinking.

4.3

Professional evaluation

The professionals who evaluated the students’ work gave very similar average scores to each session, though the CAD sessions were ranked slightly higher than the studio sessions. Among the four dimensions, the scores indicate

Figure

12

Professional

evaluation

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that the studio sessions were stronger in formal generation and composition, whereas the CAD sessions excelled on solar energy control (Figures 11 and 12). Based on the observations from jury members who had seen students work from the same project in the past, the four sessions were deemed to be of a higher standard than previous years, especially in the originality of ideation, space planning, formal composition, control of daylighting, and views. However, the craftsmanship of the final physical models were not as strong as in the past, since the overall time frame of the project remained untouched while the content expanded with the integration of digital building performance as a key element in the design process.

5

Conclusion and discussions

This research investigated the effectiveness of PBD in assisting student learning and performance in beginning interior design education. The results indicated the overall success of the PBD which was structured as an intermixed use of digital and non-digital media. Digital simulation of building performance impacted the design process and improved the design outcome. The PBD approach was effective in gaining an early awareness of sustainable energy for beginning interior design students. It also enhanced students’ understanding of the mutual relationship between interior and exterior and between the man-made and the natural environments. The interaction and atmosphere in the experimental sessions differed greatly from previous, more traditional and prescriptive courses, which presented the potential of a more interactive and engaging learning environment through the application of digital simulation tools. The results also affirmed the power of paper-based media for visual reasoning, especially in the conceptualization stage. This study successfully responded to the transformation of PBD in design practice. However, interior design educators face a number of challenges for the future growth of PBD in the profession. The lack of resources and training opportunities hinders teachers who are working to keep pace with the fast development of digital technologies. One of the jurors, who will teach the same studio in the following semester, expressed such concern. Unfortunately, she was not alone. It is not debatable that design faculty has to seek technical and financial support within academia and from software vendors and design practitioners to advance their knowledge base in the digital field. Educators also have to address the pedagogical challenge of fitting the expanding design knowledge and techniques into the already full curriculum. They must be more creative in their teaching so that digital technologies could be effectively integrated into the design process and the learning environment could be more engaging and inspiring. In addition, the disparity between the software industry and the design professions impede the widespread use of PBD in academia. Many existing software

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applications have sharp learning curves and are designed for industry experts. Most simulation activities are achieved through iteration, which means that processing through several software programs may be necessary. For design students, simple, visually-oriented tools and procedures which produce an approximate simulation may be more appropriate than complicated professional tools. Such demands require the academy, the computer specialists, and the building industry to continue their collaboration on the invention of better tools. A more seamless integration of digital technologies into design activities could be accomplished in the foreseeable future. This study was the first step of a longer project to investigate the scope of integrating PBD in interior design education. The setup of the project in both studio and CAD courses shows the potential of a PBD approach to be applied in various interior design courses which involve building performance elements. Meanwhile, further investigation is necessary on comparing the workload of employing digital and non-digital tools so that the process and outcome of the work can be continually improved. No matter the challenges, obstacles, and concerns, interior designers, as one of the team players in sustainable design, should be better prepared with new knowledge and new skills for future viability within this growing field. Accordingly, it is increasingly necessary that interior design programs accommodate PBD as one of the new design processes and methods within the curriculum.

Supplementary material Supplementary material associated with this paper can be found in the online version at doi:10.1016/j.destud.2009.12.002.

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