Photorealistic vs. Non-Photorealistic Renderings

in Virtual Environments

Runddy D. Ramilo, MSc, BSc (Arch) PhD (Architecture) candidate, Australia

Abstract

Design is a creative activity that is complex and influenced by numerous factors. The new trend in design presentations explore and takes place in a Virtual Environments wherein computer-simulated environment is used to communicate and perceive design. Most researches on Virtual Environments (VE) have been focused on Photorealistic (PR) simulation environments but there has been inadequate research on the use of VE in Non-Photorealistic (NPR) presentations to explore the most efficient method of interior design presentation.

This article discusses the use of VE to support the necessary means of interior design presentations i.e. Photorealistic or Non-photorealistic Renderings. Perception of spatial volumes within VE is assessed through comparison of representations using Photorealistic and Non-photorealistic means of presentations. A research was conducted to investigate the relative effectiveness of both Photorealistic and Non-photorealistic in immersive and non-immersive VE by interpretation and communication through design. It was found out that Non-photorealistic renderings are still the most preferred method of renderings by designers and clients.

Keywords: Virtual Environments, Design, Photorealistic, Non-photorealistic Renderings

Virtual reality is a technology which allows a user to interact with a computer-simulated environment. Most current virtual  environments are primarily made for visual experiences that displayed either on a computer screen or stereoscopic displays with simulations which include additional sensory information, such as sound through speakers or headphones. Immersive Virtual Environments (IVEs) perceptually surrounds the user, increasing the user’s sense of presence being within it. Virtual environments have been increasingly used for a variety of contexts such as learning, business, engineering, architecture and design.

As the modern world develops and utilizes design technology for architecture and interior design, the subsequent demand for digital presentations had popularly emerged. Current visualization research have focused on achieving Photorealism (PR) in which essentially concerned with rendering images as ‘realistically’ as possible through the integration of physics and algorithms (Halper et al, 2003). In virtual environments walkthroughs and picture-perfect simulations of objects have defined a practice where Photorealism  is considered as perhaps the most important measure of a successful representation (Roussou and Drettakis, 2003). Since its emergence, the field of computer graphics has concentrated on making 3d images that are indistinguishable from reality. Figure 1 and 2 are examples of Photorealistic interior design presentation from Wilson and Associates, world’s leading interior design firm.

hi runddy images to follow

On the other hand, while most designers and researchers in design and computer graphics have focused on creating Photorealistic presentations some have concentrated on Non-photorealistic presentations. Some have evaded the use of technology and most are inspired by human drawing techniques that are water color, pen and ink, crayons, markers and pencils. With the traditional techniques and human skills a lot in interior design practice are still using these means of presentations as it relates to creative and artistic creations of designs. According to Mausch and Magdeburg (2002), Non-photorealistic renderings (NPR) are beneficial in many ways as they can support story telling, expressive, giving the image a certain artistic look and feel. Masuch and Rober (2001) also encourage the use of NPR as a good alternative as it is more artistic and convey a creative sense of design. A number of research article (Harper et al, 2003), (Kang, 2000) and Klein et al, 2000) states that Non-photorealistic .renditions appear more natural and are perceived far more easily than complicated technical drawings. Figure 3 and 4 are examples of Non-photorealistic in water color and figure 3 and 4 interior design presentation from Wilson and Associates and Designphase Hospitality respectively.

Design Presentations in Practice

In the beginning of the emergence of digital presentations in interior design, many have been enthusiasts and have taken advantages on the use of technology for precise creation of design and presentations. Several designers have focused in 3d modelling and construction detailing and others started creating designs in 3d worlds.

Several big architectural and interior design firms like KPF, Aedas, HOK and many others appears to intentionally trash out the traditional non-photorealistic means of presentations and have shifted to 3d modelling resulting to produce a Photorealistic rendition that range from still life to walkthrough animations. Ramilo (2007) points out that Photorealistic renderings has been a good tool for visual communication wherein architects and designers can portray their imaginations into virtual reality. This provides the opportunity to extract the best from variety of different designs for built environment and realizing emotions of interior spaces.

However, as the field of digital media is becoming mature and virtual itself starts to develop a ‘picturesque language’ and even more realistic, there is a realization that in many cases what may interest is not so much about Photorealistic presentations but an image that communicates and easily perceive its underlying meaning. World’s leading interior design companies like Hirsch Bedner and Associates, Wilson and Associates, and Gensler are still using the traditional Non-photorealistic presentations and believed that it is about design as creating creative spaces and convincing environments, regardless if the imagery realistically emulates the physical properties of the world or not. Furthermore, as Photorealistic rendition is technically tedious and costly in which consumed a lot more time and efforts than Non-photorealistic. In many small and medium size design companies, Non-photorealistic  presentations appears to be more efficient as it can be done with several styles and options that is water colors, markers and others; in a lesser efforts that can be done by most of the designers. The table 1 below is a simple graphical representation that shows considerable types of design presentations that is currently used in interior design practice.

Table 1. Graphical representation of design presentations by the Author

Nowadays, finding the most quoted efficient interior design presentations has been a difficult task. What may appear graphically good and meaningful to other clients might be worst to other people with different background. In this study, it is argued that design is not just about form and images but about different layers of meanings. Interior spaces can be associated with different functional activities and values which may form a rich environment and cannot be understood by just watching ‘photorealistic’ representation instead ‘imbuing’ the place. For a better understanding and experience in a virtual design environment the most engaging environment is required, which may not necessarily be the most graphically realistic environment.

Visualization Issues

Despite of comparable technical research (Strothotte & Schlechtweg 2002) within non-photorealistic rendering (NPR), research doesn’t exist in evaluating psychological knowledge regarding its effect on human cognition and perception in interior design presentations. While the Photorealistic image is defined by the singular principle of appearing as realistic or ‘life-like’ as technologically possible, the Non- Normal 0 photorealistic image is virtually infinite and artistic and appears to have variety of styles (Harper, 2003).  The visual flexibility of Non-photorealistic holds inherent, though still undefined, potential to influence viewer responses in a variety of manners.

Conclusions

Non-photorealistic renderings (NPR) have long proven useful in the fields of architecture and urban planning: presentation techniques initiated by the Berkeley Environmental Simulation Laboratory (Appleyard & Craik 1978) have been designed to improve user needs when viewing planning alternatives. Additionally, communication between experts and laymen has also developed due to improvements in CAD, visualization, and simulation (Linneweber 1993). In terms of laymen—citizens, investors, and future users, participatory designs must facilitate interactions as well as basic design understanding.

Schumann et al. (1996) demonstrated that Non-photorealistic renderings (NPR sketch-rendered design qualitatively improves the dialogue between architects and clients, in contrast with dialogues elicited from Photorealistic renderings (PR) images. Psychologically, sketch-rendered designs maintain different affordances (Gibson 1977; Munz 1989), wherein sketched images appear preliminary, unfinished, and therefore open to change. Thus, the client is more likely to consider and suggest changes to the design. NPR can also be employed to guide behavior. Halper et al. (2003) demonstrates that increased levels of detail can effectively influence both navigation and exploration behaviors, wherein subjects asked to choose a path to explore or reach a goal in the distance tend to select the path with the higher levels of detail PR images. Potentially, subjects view in an increased level of detail PR is more interesting for exploration, relative to lower level of detail NPR.

References

Appleyard, D., & Craik, K. H. (1978). The Berkeley Environmental Simulation Laboratory and its research programme. In: International Review of Applied Psychology, 27, 53–55.

Halper, N. Mellin, M. et al (2003) Psychology and Non-Photorealistic Renderings: The       Beginning of a Beautful Relationship, in mensch and Computer, Interaktion in Bewegung Stuttgart B. G. Teubner S. 277-286

Halper, N., Mellin, M., Duke, D., & Strothotte, T. (2003). Implicational rendering: drawing on latent human knowledge. Submitted for publication.

Gibson, J. J. (1977). The theory of affordances. In: R. Shaw & J. Bransford (Eds.), Perceiving, Acting, and Knowing (pp. 67–82). Hillsdale, NJ: Lawrence Erlbaum.

Kang, H. (2000) Non-photorealistic Virtual Environment Navigation from Images, Department of Mathematics and Computer Science, University of Missouri - St. Louis, One University Blvd. St. Louis, MO 63121, USA

Klein, A., Li, W. et al, (2000) Non-Photorealistic Virtual Environments, Princeton University Press

Linneweber (1993) Linneweber, V. (1993). Wer sind die Experten? "User needs analysis" (UNA), "post occupancy evaluation" (POE) und Städtebau aus sozial- und umweltpsychologischer Perspektive. In: H. J. Harloff (Ed.), Psychologie des Wohnungs- und Siedlungsbaus: Psychologie im Dienste von Architektur und Stadtplanung

Masuch, M. and Rober, N. (2001) Game Graphics Beyond Realism: Then, Now, and Tomorrow, Otto-von-Guericke University Magdeburg Games and Graphics Research Group Institute for Simulation and Computer Graphics

Munz, C. (1989). Der ökologische Ansatz zur visuellen Wahrnehmung: Gibsons Theorie der Entnahme optischer Information. In: Psychologische Rundschau, 40, 63–75.

Roussou, M. and Drettakis, G. (2003) Photorealism and Non-photorealism in Virtual Heritage Representation, First Workshop on Graphics and Cultural Heritage in Chambers, A.  and Arnold, D. UK.

Ramilo, R. (2007) Virtual Interior Space,  National Library, Manila, Philippines
ISBN 978-971-93919-0-6

Strothotte, Th., & Schlechtweg, S. (2002). Non-Photorealistic Computer Graphics: Modeling,Rendering, and Animation. San Francisco: Morgan Kaufmann.

Schumann, J., Strothotte, Th., Raab, A., & Laser, S. (1996) Assessing the effect of nonphotorealistic rendered images in CAD. S.G.R. Bilger & M. Tauber (Eds.), Proc. Computer Human Interaction (CHI’96), pp. 35–42, ACM Press.