USE OF 3-D MODELLING AS AN INTERACTIVE PRESENTATION AND CONCEPTUAL DESIGN TOOL

Paul Hsu
Landscape Architecture Program
Oklahoma State University
360 Ag. Hall
Stillwater, OK 74078
E-mail: PHSU@okway.okstate.edu

ABSTRACT

A model is a simplified representation of the real world. Design is an interactive process and so is 3-D modelling and animation. Landscape architects develop study models (a broader meaning) of site plans and design through the use of graphic language, written communication, model building, and design language. 3-D modelling opens a new frontier in landscape architecture design visualization for designers and educators. This paper presents the experience of teaching 3-D spatial modelling. By incorporating 3-D modelling and the animation of visualization tools into design courses, students were able to visualize their designs better. More specifically, students and instructors were able to create a real-time animation of the site at a selected path with an interactive presentation that opens the spectrum of discussion. Sequential spatial experience, design languages, and design principles can be understood in a dynamic way. 3-D modelling and visualization techniques are unique and useful spatial design communication tools. These techniques also provide designers with better design ideas and decision-making processes through interactive experience, conceptualization, imagination, and judgment. This paper also assesses the impact, success and problems of this innovative design education method.

INTRODUCTION

Traditionally, landscape architecture design communication is achieved through the presentation of 2-D plan graphics, projections, and perspective drawings. With the advance of computer technology, many architectural and spatial modelling software have been ushered into the 3-D modelling and animation era. Interactive presentation is an ideal use for real-time animation on a computer. What is a real-time interactive presentation? Instead of confining clients or critics to the examination of 2-D plan drawings or a physical model, spatial modelling applications allow users to control a presentation, creating a path through and around its various segments in a virtual reality. A perception and understanding of the designer's ideas are achieved by walking through, climbing over, getting inside, flying over, and looking underneath any objects, buildings, plants, or whatever can be modelled in three dimensions on a computer screen. Sequential spatial experience, design languages, and design principles can therefore be understood in a dynamic way.

A majority of the Computer Aided Design (CAD) software currently taught in design classes does not provide the capabilities of real-time interactive presentations. CAD software is an excellent tool for creating two- and three-dimensional geometric space. With CAD one can easily create a house, a tree, and a car with proper dimensions; however, one can't walk through a 3-D model and look through different perspectives and spatial sequences while examining the designer's concepts. By incorporating 3-D modelling and the animation of visualization tools into design courses, students will be able to visualize their designs better. What is more important, students and instructors will be able to create a real-time animation of the site at a selected path with an interactive presentation that is convincing. This interactive presentation tool is also applicable to the interior designer, architect, engineer, and other professionals who want to walk through their designs before they commit themselves and their clients to the execution of a plan or to the building of an expensive physical model.

This paper presents the experience of teaching 3-D spatial modelling with the following spatial design subjects in mind--abstraction in 3-D space; sun, shadow, and solar dwelling in 3-D; landform and structure in 3-D; spatial sequence in 3-D; and vehicular movement and viewshed analysis in 3-D. Each subject was studied by an individual student. This paper also assesses the impact and success or problems of this innovative design education method. The 3-D modelling process versus the traditional design process was documented. The innovative methods of interactive presentation were further analyzed as the projects progressed. Rendering of objects, the effects of natural sunlight and artificial light sources, the effect of walk-through and fly-by in a site, the ease of creating perspective drawings with hidden surfaces at different standpoints, and the effects of moving images of a digital video presentation were studied. Time saving factors and the teaching experience were assessed. At the end, we concluded that 3-D modelling and visualization techniques are unique and useful spatial design communication tools.

MODELLING AND THE DESIGN PROCESS

In a typical design project, a designer's thought processes evolve from idea conceiving, real world conceptualizing, site analysis, programming, model building, evaluation, to preliminary design. Deriving models such as schematic diagrams, project flow charts, suitability maps, and 3-D computer models for designers are part of the design process. These abstraction models help designers mature, design, predict, and critique design alternatives efficiently, inexpensively, and harmlessly.

Fig. 1: Computer modelling and design process

Landscape architects are involved in many decision-making processes in their daily practice. Designers would generally approach the problems by processing the available information of the site (the real world), considering the interrelationships of site entities, developing a mental model with criteria, opportunities, and constraints. At the same time, designers start to develop different concepts and ideas for the design solution though these concepts may not be mature until later on stage. The next important stage for designers is to analyze the site, develop programs, goals, and objectives. Design principles, design theories, and methodologies are used to ferment design concepts and solutions. A crude model of site plan and design is evolving gradually through the use of graphic language, written communication, model building, and design language. Design critics come in at this time to evaluate the design solution and refine the ideas further along with principles and theories of design. The designers usually take the analytical results back to the analysis stage for improvement. In order to have an efficient way of examining a design, designers may build physical models, make symbolic models, or create mental models to help out in this process. These models provide a basis for evaluation and possibly for animation and simulation studies that direct designer to a feasible solution, satisfactory solution, optimum solution, or no solution at all to practical problems [Neelamkavil, 87]. Preliminary design is the result of the modelling and design process of a designer.

What is a model? Are we suggesting a fashion model in the swimsuit edition of Sports Illustrated? Or, are we implying that a model is like a model house that a developer uses to show to prospective buyers? John Casti in his book "Alternate Reality" suggests that, "A model is a mathematical representation of a modeler's reality, a way of capturing some aspects of a given reality within the framework of a mathematical apparatus that provides us with means for exploring the properties of that reality mirrored in the model." Let us rephrase this definition. A model is a simplified representation of the real world intended to enhance our ability to understand, predict, and possibly control the behavior of the real world [Casti, 89; Neelamkavil, 87; Kirkby, 87].

The applications of modelling methodologies are much more widely used in science and engineering than landscape architecture where design theory orients somewhat artistically. However, landscape designers and planners are well equipped with specialized modelling techniques that we all tend to overlook. Modelling techniques which designers commonly use include physical models made of cardboard or styrofoam materials, symbolic models like schematic maps, functional diagrams, and written descriptions, pictures, and computer graphics, and mental models of individual creation. Graphic language is as important and logical as verbal language (natural) or computer language (formal). This paper does not intend to cover all the investigations of different models and the logistic methodology of them. The intention of this paper is to explore the use of 3-D modelling as an interactive presentation and conceptual design tool.

SIMULATION, ANIMATION, & COMPUTER VISUALIZATION

One can trace the historical use of computer applications in landscape architecture design studios back to circa 1980 when desktop computing became a reality. Computer integration in the landscape architectural educational process was mainly with word-processing, pixels oriented graphics, object oriented graphics, spreadsheet, database, and desk top publishing [Sherman, 88, Hsu 85]. Today computer applications have increased their domain. In addition to the above applications, many educators use Geographic Information Systems (GIS), Computer Aided Design and Drafting (CADD), Video Image Capture, 3-D Modelling and Animation, and Design Image Visualization [Chenoweth, 91; Gimblett, 90; Ervin, 92; Orland 92; Landphair et. al, 88].

3-D modelling opens a new frontier in landscape architecture design visualization for designers and educators. By using computer animation and 3-D modelling, designers are able to visualize their design and may better understand how various phenomena evolve in space and time. Designers use computer software to build 3-D graphic objects using geometric modelling techniques. Designers then apply keyframe animation techniques to visualize their design using virtual cameras and artificial light sources. Computer animation is defined as a technique in which the illusion of movement is created by photographing a series of individual drawings on successive frames of film [Thalmann, 90]. Keyframe animation is created by giving the computer a certain number of stops or frames, called keyframes, and the computer derives the other frames using interpolation or "tweening" (stand for in between) procedures.

Computer modelling and simulation emerged as an identifiable numerical problem-solving technique during World War II for solving neutron diffusion problems. However, the application of modelling and simulation for solving real-life problems in several disciplines, and the expected advances in computer technology indicate that this trend will come [Neelamkavil, 87].

WHY 3-D MODELLING?

Humans see things in 3-D and conceptualize objects with attached meanings. Every object as a perceptible entity exists in time as well as in space. Designers generally convert these images into 2-D graphics or symbols for interpretation and presentation. It is difficult to comprehend an entire space from one point of observation at one time. It is the continuation of perceptible and cognitive knowledge that make a site design overall assessable. 3-D modelling is a simplified representation of a designed space, and animation and simulation are the process of imitating the behavior and phenomena of the space in selected time domain. It would be safe to say that 3-D modelling is an interactive and experimental problem solving technique.

3-D modelling aids the designers in their planning and decision-making processes. By "walking" through the model many times, designers may acquire better ideas about how the design works through interactive experience, conceptualization, imagination, and judgment. Designers also can experiment different traveling paths, interactive ongoing activities, and even design layout arrangements. Designers can further evaluate the design system according to the design theories and principles they introduced. Certainly, 3-D modelling provides a unique opportunity to experience a system that is non-existent. Designers do not have to commit themselves to build an expensive prototype or physical models until all ground rules are checked out.

However, 3-D modelling in design does come with some disadvantages. As we mentioned before, 3-D modelling for design provides qualitative analysis but has difficulty in quantitative analysis. It is neither a science nor an art, but a combination of both. It is an iterative, experimental problem solving technique [Neelamkavil, 87]. 3-D modelling is best used at the conceptual design stage that iterative design process is most beneficial. The analyses of 3-D modelling results require trained professionals with good design knowledge and interpretation skills, without that 3-D modelling is going to be just a fancy tool and pretty pictures.

3-D MODELLING AS DESIGN TOOL

Design is a complicated and interwoven thought process. The real world is complex and analogous. A design is a system that applies principles and theories to design components or variables and exhibits forms and functions as a complex whole. We could link the design system analysis and computer modelling by representing the system as a mathematical expression. All design systems are subject to input (X) which is transformed by the system (S) to provide output (Y). Thus

Y = S (X)

It is up to a designer to decide how many variables must be considered in a design system. Since we cannot easily find out how a single variable influences a design process, a simulated model helps us to investigate such controls theoretically [Kirkby, 87]. By running a large number of simulations, the designer can build up the idea how a design will work and what will be the limits of a design. Let us use one simple example. Assume a designer is siting a building on a hilly slope and wants to understand how the sun/shadow effects on the design. A 3-D computer model can be built and the parameters of the date, time, location (longitude/latitude), and height and shape of the building can be input accordingly. A designer then uses the computer to simulate the effect of sun/shadow on his/her design at various angles of view and duration of time. In this exercise, the simulation model helps the designer to "postdict" the result of a site design as well as "predict" the outcome of future observations.

Fig. 2: Sun and shadow (Author)

Modelling is the process of establishing interrelationships between important entities of a system, and models are expressed in terms of goals, performance criteria, and constraints [Neelamkavil, 87]. Although many of the current 3-D modelling software do not provide a quantitative type of analysis, however, they do provide a good qualitative type of analysis. Questions like "how many store fronts have we passed by?" or "how fast is the car going?" are difficult to query from the computer. However, questions like "what might it look like if we plant trees this way?" or "what kind of feeling can one get from walking through alternately closed and open spaces?" can be perceived and shaped into the observers mental model.

INTERACTIVE PRESENTATION

This paper focuses on two major issues:

1.) to teach and apply this increasingly important design and visualization tool as part of the thinking, planning, conceptualizing, and doodling activities of the design process in design courses;

2.) to promote this interactive presentation method to other educators on campus and professionals nationwide.

Design communication is a process of setting goals, choosing methods, using techniques, and applying tools effectively. Human beings visualize the real world through perception and cognition, and then, we process this information in our minds and souls to give a reaction or action. Computer systems enable us to enhance our perceptions and amplify our actions. They also allow people to experience an artificial reality. Computer technology can aid in the development of a conceptual understanding at the same time that it helps to generate practical design skills.

By incorporating 3-D modelling and the animation of visualization tools into design courses, students will be able to visualize their designs better. What is more important, students and instructors will be able to create a real-time animation of the site at a selected path with an interactive presentation that is convincing. This interactive presentation tool is also applicable to other design and planning professionals who want to walk through their designs before they commit themselves and their clients to the execution of a plan or to the building of an expensive physical model.

EMPIRICAL STUDIES

In the Fall of 1991 this project was conducted as an experiment among a group of students. Approximately 17 students enrolled in Landscape Architecture Design Studio I and 7 students enrolled in a Landscape Architecture Special Problems Course. For our convenience, the students in Design I will be called Group A and the students in Special Problems will be called Group B hereinafter. Group A students were given a project entitled "Spatial Development in 3-D" where they needed to use landform, 15 buildings, water, and vegetation as design elements to develop a 3-D landscape architectural space. The entire project lasted for approximately two and half weeks for group A and 12 weeks for group B.

Fig. 3: Experiencing the river run (Greg Sutton)

Group A students were first asked to use conventional paper sketching and drawing to develop their concept, then they were allowed to build their model with 3-D software, and finally they entered the last phase of the physical model building. Group B students who were mostly upper level students who took this special problem's course as an independent study. Course content included the method of 3-D modelling and animation with the following spatial design subjects in mind--abstraction in 3-D space; sun, shadow, and solar dwelling in 3-D; landform and structure in 3-D; spatial sequence in 3-D; and vehicular movement and vista analysis in 3-D.

In both classes, group A and B students were taught how to use the software, the terminology of 3-D modelling, animation, views, and walk through. Group A students were required to capture two to three of their best views. They did not have time to go into the animation stage. However, Group A students were exercising their project with the method of parallel learning process in mind--traditional drawing, computer modelling, and physical modelling. Group B students selected an individual study subject and designed a plan on paper and on the computer respectively. Once a drawing of the study site had been created, standpoints were changed and different views were created. Group B students decided the best route for a spatial sequence of a site visit and determined views, stopping points, and the speed of walk through and fly-by. These views later became the key places and links for creating frames of animation or digital video, moving images through a process called 'tweening.' Music or narration was added to make a persuasive and even more effective presentation.

The advantage of using 3-D modelling as a conceptual design tool lies in its flexibility and speed of creating different perspective views from any angles instantly. The software also allows us to "fly" or "view" in a real-time manner. For less complicated drawings, walking through and flying-by a designated site with rendering effects is instantaneous, this is commonly called virtual reality. For complicated drawings, the real-time walk through or fly-by will show its sluggishness due to the wait needed for rendering. However, this in no way hinders the conceptual or perceptual thought processes. The rendering of a frame usually takes approximately 1 second to 2 minutes depending on the complexity of the drawings. The software also allows students to export animation to a film-making software for digital-video presentation.

Fig. 4: Vehicular Movement (Scott Eccleston)

To create a successful animation, one should pay attention to the frame rate of animation as well as the speed of walk-by. The frame rate alone cannot decide the overall presentation. For example, to animate the sun shadow movement of day and night is quite different from the animation of pedestrian mall experience. Shadow movement is like the photographic time-lapse technique where an image at certain times of the day is recorded (e.g., at an increment of 15 minutes from 6 a.m. to 8 p.m.) and then replayed at a faster speed. In a spatial sequence of a pedestrian mall, one would want to stroll very slowly. This means at a shorter distance more imaging frames are going to be required. Also more disk memory for the overall presentation would be needed. In general, at a slower speed of traveling, more details of object representation are also required to make the presentation more meaningful. Reducing the frame rate of the animation does change the relative speed of the presentation but does not improve the perceptual quality of the presentation.

ASSESSMENT OF THE IMPACT

It is important to assess the impact and success or problems of this innovative design education method. At least three areas could be addressed:

1.) The differences between the 3-D modelling process vs. the traditional design process need to be identified and documented.

2.) The innovative methods of interactive presentation can be further analyzed along with the progress of projects.

3.) The time saving factors and teaching experience can be assessed.

At the end of the project, students from both groups were asked a few questions to determine the relative success or problems of this project experiment. The first three questions asked were:

1. Do you think that this project helped you to better understand the use of landform, structure, water, and vegetation as design elements?

2. Did the computer model building process help you to better understand the 3-D concept of spatial design?

3. You were asked to do the design process in three ways: sketching and drafting on paper, building a model on computer, and constructing a physical model. This teaching method is called parallel processing. Do you think that the parallel processing method helped you to better understand the design process?

The responses from both student groups were very positive. Almost all students responded yes to three questions. One student thought that the computer model did not help due to software glitches while two other students were not sure due to their lack of computer knowledge. One student didn't quite understand what parallel processing means. However, this particular student has a very low motivation in class assignments.

Students were asked about the disadvantage of the 3-D computer modelling process. Most of Group A students consider the lack of computer knowledge as the disadvantage in using 3-D modelling software. Some students felt that the ability to render a model--create 3-D views with shading, object edges, and shadows--were somewhat limited and unrealistic. There were other disadvantages such as the printer output used for sticky back blueprint was not sharp enough; too much time was spent on the computer; and too little time to learn, etc. Group B students didn't consider the time spent as a negative factor perhaps because they were more mature in computer skills. On the contrary, they valued very highly the ability to use 3-D animation to see every aspect of their design by creating views in a particular sequence that would give one the actual feeling of visualization in space. Many Group A students thought that computer provided them with an opportunity to visualize 3-D easier especially when they had trouble transforming 3-D vision in their minds to paper. Many Group B students thought that animation helps a designer feels a sense of being in the design themselves, and that the project did seem to come to life with the real time animation.

Figure 5: Project Experiment Impact Assessment

CONCLUSION

At the end of this study, we found that 3-D modelling and visualization techniques are unique and useful spatial design communication tools. These techniques can be applied all design professionals as a modelling and design process tool for years to come. These techniques also provide designers with better design ideas and decision-making process through interactive experience, conceptualization, imagination, and judgment. Students need to spend time on this type of project to completely understand and appreciate the technology. Students ought to understand that this spatial design method is provided as a conceptual design phase that gives the designer an opportunity to understand their designs better.

Renderings and animation reproduced for this article were created using the following equipment:

Hardware -- Macintosh IIci and IIsi, 8 bit color, EasyVideo 8, Panasonic VHS

Software -- ModelShop II, Swivel 3D, PowerPoint

BIBLIOGRAPHY

Casti, John. 1989. Alternate Realities: Mathematical Models of Nature and Man. New York: John Wiley and Sons, Inc.

Chenoweth, Richard. 1991. "Aesthetic Policy Implication of Image Processing Technology." URISA Journal -- URISA, Vol. 3, No. 1, pp. 6-13.

Ervin, Stephen. 1992. "Integrating Visual and Environmental Analysis in Site Planning and Design." GIS World. URISA Special Issue, July 92, pp. 26-30. Fort Collins, CO: GIS World, Inc.

Gimblett, Randy. 1990. "Visualizations: Linking Dynamic Spatial Models with Computer Graphic Algorithms for Simulating the effects of Resource Planning and Management Decisions." URISA Journal -- URISA, Vol. 2, No. 2, pp. 26-34.

Hsu, Po-Siu and Betsy Boehm Hsu. 1985. "Microcomputer Education in Landscape Architecture Design/Build Practice." NACTA Journal, Vol. XXIX, No. 1, pp. 69-71.

Hsu, Po-Siu. 1992. "Spatial Structure and Design Process: A Step Towards an Ideal Information System for Design and Planning." Proceedings of the ASPRS/ACSM Conference, 6-10 Mar. Alberquque, NM.

Kirkby, M. J. et. al. 1987. Computer Simulation in Physical Geography. New York: John Wiley and Sons, Inc.

Landphair, Harlow. Cunnis, Ed. 1988. "Computer Applications in Design of the Driving Environment: An Integrated Approach." Proceedings of the Educational Sessions, ASLA Open Committee on Computers, '88 Annual Meeting. pp. 9-14.

Laseau, Paul., 1980. Graphic Thinking for Architects and Designers. New York: Van Nostrand Reinhold Company.

Neelamkavil, Francis. 1987. Computer Simulation and Modelling. New York: John Wiley and Sons, Inc.

Orland, Brian. 1992. "Shaping Landscape Visions: Some Implications of Computer Visualization for Design Practice." L.A. Letter. June 92, Vol. 3, No. 2. Washington, DC: ASLA. pp. 2-5.

Sherman, Michael. 1988. "Issues for Computer in Landscape Architecture Education: A Case Study for Success." Proceedings of the Educational Sessions, ASLA Open Committee on Computers, '88 Annual Meeting. pp. 31-36.

Thalmann, Nadia Magnenat. 1990. Computer Animation: A Tool that Gives Life to Visualization. Ch. 8. pp. 113-127. Scientific Visualization and Graphic Simulation / Edited by Daniel Thalmann. New York: John Wiley and Sons, Inc.

Tufte, E. 1987. The Visual Display of Quantitative Information. Cheshire, CT: Graphic Press.

Wyvill, Brian. 1990. A Computer Animation Tutorial. Ch. 4. pp. 235-284. Computer Graphics Techniques: Theories and Practice / Edited by David F. Roger, Et. al. New York: Springer-Verlag.

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