A MULT IMODAL DESIGN ENVIRONMENT

This paper describes a multimodal environment to support all stages of the industrial design process. The system is considered to support a designer starting at the very early stages of the design process up to the production and reengineering of physical models. This switching between the virtual and the physical world is called multimodal. To deal with all those stages, the system's architecture comprises commercially available tools as well as completely new developed components. This architecture is presented and some parts of it will be described in detail . Special emphasis is placed on the kernel of the system, a VR-modeling tool and on its user interface. An overview of the provided interfaces from and to the physical world, and an outlook on further work complete this paper. THE " designDesign" -WORKSHOP Nowadays, product design is a highly complex and creative task, carried out under a number of constraints such as time and costs. The design process not only focuses on creating the shape for a new product, but comprises the whole range of product development, starting with the recognition of a "real-world problem" which is to be solved, and ending with the production of a first prototype. Several phases of the design process can be supported by computer modeling tools, while others cannot. The very early stages, also called "conceptual phases", only depend on the experience, view, and creativity of the designer. There is no process description for these early stages and a designer can hardly explain how he deals with them. In these stages, design is an entirely mental process dealing only with ideas and thoughts (Hofmann 1998). During the subsequent stages of design named visualization -, there is a strong need for supporting the designer with tools. In this case, the definition of tools comprises digital tools as well as physical ones. The main idea described in this paper is to combine these two worlds, physical and digital, and to allow a designer to switch easily between them (Weinert et al. 1998b). To achieve this goal there are many ideas and conclusions which were developed during a workshop held in Stuttgart in June 1998. 22 designers from several fields of design (architecture, industrial design, WWW-design, etc.) took part in the workshop and discussed their needs for additional digital and physical tools to improve their personal design processes. A technique called brainwriting was used to extract fundamental ideas and gather opinions. Those fundamental ideas are now serving as a basis for the proposed Multimodal Design Environment (MDE) (Hofmann 1998). These ideas are summarized in the following fig. 1: Fig. 1: Multimodal Design Process Digital vs. Physical Modeling It turned out that designers wish to use digital models for various reasons: x A digital model allows fast and easy changes of material, shape, lighting, color, etc. x Duplication and transportation of digital models are fast, low-cost operations. Variants can be generated with littl e extra effort, and close co-operation with colleagues and/or customers around the world becomes feasible. x A digital model is directly available for computer processing, e.g., stress or flow simulations and CAD/CAM-production. On the other hand, there are several reasons why designers are not likely to abandon physical models: x A physical model can be touched, and it has a weight. x There are properties of a model which cannot be simulated nowadays, like flavor and smelling, and even some geometric aspects must be felt by hand. x Many designers are used to physical models and have acquired high levels of skill with physical tools. Some see no need for digital tools and cannot imagine using them in a reasonable way. MDE is an approach to integrate both worlds in one design process by providing fast and easy transitions between them. This is necessary in order to combine the advantages of both worlds by avoiding their respective disadvantages. THE MULT IMODAL DESIGN ENVIRONMENT The MDE comprises a variety of different tools which are designed to work together closely. There are standard CAD/CAM-tools as well as a newly developed VR-modeling tool. Not all of them are running in a VR environment because for such tasks as surface reconstruction and NC-data generation there is no need to carry them out in an highly immersive environment. On the other hand, generation of new shapes or changing an existing virtual model are tasks which recommend an immersive VR environment. The following fig. 2 shows the overall structure of (the computer-based part of) the system. Fig. 2: Overall System Structure The figure shown above presents basically three layers and the degree of immersions grows from the outer to the inner circle. Between the layers there have to be interfaces which are described later in more detail . It is important to notice that the overall system structure comprises more than the VR-modeler and that only the co-operation of different tools on different levels will help designers in different stages of design. The next paragraph first describes in more detail the VR-modeler, the different tools it provides and their impact on the chosen data representation. The interaction concept is central to a further paragraph. At last, the tools and interfaces which are used to change the virtual models into physical ones and vice versa are presented.