Issues in Styling and Engineering Design

Keynote Papers

Issues in Styling and Engineering Design Fumihiko Kimuia (1) Department of Precision Machinery Engineering, The University of Tokyo, Tokyo, Japan

Abstract The aim of this paper is to review the present development of styling design activities in product design processes, and to identify new roles and technology of styling design to cope with emerging market and environmental requirements in our society. The focus of the paper is to analyze the interplay between styling and engineering design. The importance of product aesthetics is investigated in comparison with ergonomic and technological factors, and many example products are analyzed, such as automobiles, electromechanical products, etc. Computer aided tools for styling design are reviewed, and future issues are identified for enabling high-quality styling design and tight integration with engineering activities.

Keywords: Styling Design, Engineering Design, Computer Aided Design

1. I n t r o d u c t i o n

Due to the high competition in global market, it is increasingly important, for producing value-additive products, to realize clear differentiation from other products. Product differentiation can be achieved by new functionality and innovative technology, but aesthetic appeal or styling is becoming essentially important in modem society. From the users' viewpoint, styling is strongly related with product usability and amenity, and one of the key components for better product acceptance. Success of new products is often attributed to the delicate combination of aesthetics and enabling technology. The aim of this paper is to review the present development of styling design activities in product design processes, and to identify new roles and technology of styling design to cope with emerging market and environmental requirements in our society. The focus of the paper is to analyze the interplay between styling and engineering design. The degree of dependence between styling and engineering design may be different according to products. The styling and engineeringdesign can be complementary or collaborative to each other, but often they are contradictory or competing to each other. The scope of the discussion in this paper is limited within engineering discipline of styling design, and does not address creative artistic design processes. Computer support for styling design is essential for coping with new requirements, and Computer Aided Styling Design is fully analyzed. In this paper, styling design is considered as an important component of Industrial Design(lD). Industrial design is defined as the 'professional service of creating and developing concepts and specifications that optimize the function, value and appearance of products and systems for mutual benefit of both user and manufacturer."(58) In this context, industrial designers focus their attention on forms and user interaction of products. Product design philosophy, appearance and utility are the major goals for industrial design in addition to engineering factors, such

Annals of the ClRP Vol. 46/2/1997

as maintenance and cost (10,15). Those goals can be roughly characterized by aesthetics and ergonomics. Ergonomics is considered to encompass all aspects of product-user interactions. Styling design is primarily concerned with aesthetics. In parallel with industrial design, engineering design is performed for detailing product functionality and manufacturability. Relations among those concepts are shown in Fig. 1.

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Fig.1 Styling and Engineering Design In the following sections, roles and evolution of styling design are considered, and relationship between styling and engineering design is discussed with industrial examples. Computer aided tools are reviewed, and future issues are summarized. 2. Roles of Styling Design in Product Development

History of styling design in industry can be traced back to the beginning of 19th century(l5). After the years that products were artistically decorated as the exterior of mechanisms, the idea "Form follows function," arose in

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Europe in early 19th century. In United States, around 1930's, there were big movements that products should be given additional value by giving a nice shape, like a streamline shape, which had weak relationship with products' functions(33). After such activities, modern concept of industrial design has emerged during the last several decades. Recently customers are more concerned with styling of products, and importance of styling in product development is decisive. Styling design is important for product differentiation. But, the degree of importance is different fromproducts to products. Typical difference with respect to industrial design is shown in fig.2(58). Technology-driven products are characterized by their technical performance to accomplish a specific function. User-driven products are based on their unique message coming from their aesthetic appeal and user interface. The separation of those types are not definite, and may change according to the change of market and technology.

(b) New design (a) Old design Fig.3 Design Example of Electron Microscope

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As considered from the above examples, it is fairly difficult to discuss, in general, styling design processes and their relationship with engineeringdesign. Simple definition of "goodness" of styling' design is not possible. Some guidelines for styling design are discussed in technical brochures(40, 41), where it is stressed the importance of the clear description of product image and tight collaboration with engineering sections for design finalization. The methodologies for product design, such as (50), could be applied for styling design, but, may need further extensions, because many factors affecting styling design do not come from physical phenomena, but come f rom psychological and physiological phenomena. For example, human perception(43) and user environment(1) are increasingly becoming important for styling design.

Two example products are shown in fig.3 and fig.4(52). In fig.3, a comparison is made for electron microscopes (a) without any care about styling and (b) with due care about styling and user interaction, but with not much difference of functions. . This is an example of products covered by "fashionabledress". Ergonomics is an important factor for this type of products. Fig.4 shows a successful example of innovative change of styling and user interaction with a close support of new technical development. This new MR Imaging device has been designed based on the concept of "Design for Healing Environment" and "Patient-Friendly". The new design has adopted an open gantry architecture which gives very safe and relaxing feeling to patients. This requires a new development of strong magnet and its configuration design. This is an example of products which requires tight collaboration of styling designers and engineers, and creation of new product concept.

Styling design is normally carried out based on trial-anderror methods. First rough product images are created by designers, and those images are gradually refined by use of sketches and three dimensional mock-ups. This cycle is repeated until satisfactory shapes can be determined. Today it is strongly required to speed up this iteration cycle in order to keep up with the rapid change of market needs without any obsolesce. For this purpose, CAD system are essential to realize concurrent activities of styling design and engineering design, as shown in fig.5. General concept of concurrent engineering(l1, 48) and product modelling(26) is valid for styling design. But proper extension is necessary to support characteristic features of styling design. For example, in order to help designers to create new product image idea, automatic generation of product image alternatives may be useful, based on candidate images from the library of past design and their modifications by

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Keynote Papers

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Styling design practice in automotive industry today is reviewed by the examples from Japanese automotive company( 16). Fig.7 shows a sequence of representative phases of styling design, as explained below: (1) Rendering sketch made by hand for planning and concept design, (2) Clay model of 1/5 scale for evaluation of concept,

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Current practice and future perspective of styling design process of automobile exterior shape is explained in this section. Here automobile styling design is selected as a representative design by the following characteristics: (1) Automobile styling is a strong differentiating factor for customers. (2)Automobile styling design process has a long history of development, and is the most established, advanced, and systematic one. (3) Requirement for quality is very severe wjth respect to both aesthetic features and engineering attributes. (4) Most advanced CAD systems are used. Current issue for automotive styling design is to reduce time required for design and to cope with increasing demand for quality of designed shape. As shown in fig.6, such issue can only be solved by re-engineeringof the total design process and systematic introduction of CAD' support. Fig.6 depicts design processes chronologically from the initial product image creation to the final determination of shape details, and summarizes thetrends of past, present and future. As rough trends of evolution, this figure can be applicable for other types of products. Fromfig.6, we can identify the following very clear trends of evolution. (a) Total time period required for design has been steadily reduced. However, the most important difference between past and future is not the reduction of time, but the change of the relative importance of each design process phase. In the past, design detailing and final drawing took a major portion of the design work, whereas, in future, planning and concept design will take most of the time, and especially drawing work can be eliminated due to the complete shape modelling in detailed design phase. (b) The usage of CAD systems will be expanded up to the planning phase, and the total design process will be integrated by CAD-based digital models. Today a lot of repeated data input is necessary, because each phase is supported by different CAD systems. (c) Manufacturing consideration will be initiated from the phase of planning. This activity will be very effective for reducing the total time required for quality of body engineering.

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Fig.7 Example of Automotive Body Styling Design

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(3)Line drawing with highlight lines for detailed design evaluation, (4) Highlight line evaluation in detail, (5) NC machining of a full-scale clay model, (6) Photo-realistic computer graphics image for colour evaluation. In fig.7, (3) to (6) are very well computer-supported, and necessary time and realized shape quality are satisfactory. But, an important item which is missing in the above process is a computer support tool in planning and concept design phases. Some trials are now being done based on commercially available tools. An example is shown in fig.8(39), which is a concept sketch made by rendering software. Commercially available software has many drawbacks for this purpose, as discussed in section 5.

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In summary, computer support for styling design in automotive industry can be said to be very powerful and effective in detailed design phase. But, for fudher reduction of cost and lead time, and quality enhancement, the following development is desired: (a) comprehensive computer support for styling concept formation, (b) integration of the total styling design and engineering design processes. 4. Styling Design for Var'ious Products

Different products have different styling design practices, and it is difficult to generalize such design processes into a unified process. Here various types of products have been selected for discussing differences of styling design influence on product design. As seen in fig.1, selected products characteristics are roughly described according to the three different factors: aesthetics, ergonomics and technology. Each product has complicated relations with those factors, but only the major relations are described in fig.9. Example product shape is shown in fig.10 (a)-(e), and is briefly examined as follows: (a) Bottle for cosmetics: Bottle shape is almost completely determined from the aesthetic viewpoint, and a strong differentiating factor for customers. (b) Ecology-conscious Personal Computer(56): This personal computer has been specially designed for realizing modular upgrade by replacing a part of the product. Main body of the computerconsists of several block modules of the same outer form, which can be

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exchanged with new ones by use of standardized block interface. And the detached modules can be reused for resource saving(1). In this example, product appearance may be of the second importance. However, this kind of products are normally not appealing to customers, so attractive appearance is quite necessary to give additional value. (c) Automatic check-in machine(40): User interface design and total environmental comfort are important for this type of machine. Adaptation of shape design to users' behaviour is a key factor for design. (d) Mobile Phone(22): Mobile phone is a typical example for complicated interaction between aesthetics, ergonomics and technology. This type of products has almost the same functionality, therefore outer shape is a strong differentiating factor for customers. But, for achieving appealing shape characteristics, new technology may be required, for example, very small size, light weight, thin shape, etc. If new device technology is'invented, it will make an innovative change of exterior shape. Technology is changing very rapidly, so speed in styling desi,gn is mandatory. (e) Bullet train(40): This high-speedtrain is operated on a route where many tunnels exist. In order to avoid sudden air pressure increase at the time of entering into tunnels, the train shape should be determined to be streamline form. For giving an impression of very high-speed train to passengers, overall shape has been design similar to aircraft. Therefore, in this case, the shape has been functionally determined, but aesthetic consideration has given additional flavour Throughout the examples in fig.10, the scale and complexity of the design processes are very different. But, basically, evolution of those design processes can be interpreted as shown in fig.6. 5. Computer Aided Tools for Styling Design

In the previous sections, styling design processes and their relationship with engineering design are reviewed with Major requirements for styling design are examples. speed of design work and quality of products. Coping with those requirements, the following two factors are

Keynote Papers

important: early computer support for design activity and integration with engineering design. In this section, requirements and issues for computer aided tools are discussed, and relevant technology is briefly surveyed. Computer aided tools are summarized in fig.1 l(24). First, requirements for computer support are summarized.

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(1) Support for idea creation: Creative thinking is always to be done by human. But, computer can help designers, for example, by offering variety of alternatives. Principle of "Least Commitment" is always important. For this requirement, very few research work has been done yet. (2) Interaction method natural for designers: Designers do not want to use computer input devices, but want to use their own tools, like sketches. At the same time, it is necessary to create new tools based on designers' requirements. (3) "Soft" geometric modelling: Current geometric modelling methods are too rigid to be flexibly used for early stages of product concept formation. Radically new idea is required. (4) Rapid prototyping: Global and precise shape evaluation can only be done on real three dimensional shape. Quick methods are required for converting computer models into real objects and vice versa. (5) Integration with engineering: In order to avoid errors in engineering deign and to improve styling design quality, early commitment of engineering design in styling design is essential. However, such involvement should not impede designers' creativity.

For inputting styling design data, there are many research works concerning with different input media and methods: drawings(l8, 25, 32), photographs(8), real threedimensional objects(l2, 30, 47) and the so-called "virtual clay model(27, 35)". Virtual clay modelling method is interesting to mimic human actions of creating physical clay models by use of virtual clay models represented in computer, as shown in fig.12. This type of practicebased methods will be very useful for early phase of style 1

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creation. Much improvement will be necessary to be accepted for real use, for instance, introduction of forcesensitive input methods(l7). Reverse engineering is a rather old subject, and it has gained a new impetus due to recent demands from styling design. An example is shown in fig.13 for model generation based on a noncontact high-speed measurement device(47). Geometric modellingis now a rather mature technology for conventional applications, such as modelling of functional components of machines by use of solid modelling. For free-form surface modelling, there are also many research works to be used for real applications, such as modelling of car body exterior shape. Free-form surface modelling is particularly impoitant for styling design. Examples are shown for car body representation in fig.14(42) and fig.l5(39). As seen from both figures, there are a lot of technical know-hows to utilize mathematical theory to real representations. Some of the surface related works include surface modellingplatform(21), irregular mesh and surface connection(34, 44), Gregory surface(2), surface features(57). For global control of surface generation in conceptual design phase, introduction of some guide principle may be useful. In this context, physical law will be effective as described in (5,19, 45). Many other Spline-basedtool for appiying and removing material

extensions are required for coping with "Soft surface modelling requirements. Drastically different approaches may be useful, for instance, voxel based approaches. There has been substantial progress concerning with shape output methods. Image generation by computer graphics has become very rapid and realistic. Example outputs are shown in fig.7-(6) and fig.16. Exact photometric simulation has been done for creating photorealistic colour in fig.7-(6)(51). By adopting new algorithms, complicated surface models can be rendered realistically almost in real time(l3, 36). This progress of quick image generation is very effective for speeding up the shape evaluation processes. Other evaluation methods for surface quality based on curvature and other geometric quantities have been also extensively developed, such as (6, 3839). Various kinds of rapid prototyping methods are becoming very popular (3, 4, 7, 20, 24, 28, 31, 37, 46, 49), and used for aesthetic and ergonomic evaluation in styling design. High-speed machining(l4) and multi-axis NC machining(23, 29, 53, 54, 55) can also be effective for rapid prototyping purpose.

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Keynote Papers

There are a lot of potential applications for Virtual Reality technology( 9). In summary, computer technology useful for styling design is progressing very rapidly, and it is very important to make comprehensive assessment of availability and effectiveness of such technology for styling design. 6. Summary

Current practice of styling design is reviewed with many examples, and interactions with engineering design is investigated. It is fairly difficult to draw unified view for styling design. As a common basis for future development, computer aided tools are essential. Shortening of design lead time requires early commitment of computer support and quality improvement with the integration of engineering design. Computer aided tools are effectively used for fulfilling such requirements. In the near future, innovative change may happen in styling design based on such technical trends, and total product development processes will also be changed.

Acknowledgment Special thanks are due to the CIRP colleagues who sent information material and documentation about their work, and gave valuable insight during the discussion at the meetings.

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