Tjamme Wiegers

Requirements for highly interactive system interfaces to support conceptual design

During the last two decades, many breakthroughs occurred in the development of CAD systems. However, some design activities are not yet successfully supported by CAD systems. This is especially true for the conceptual phase of industrial design. In this part of the process, synthesis and creativity play an important role. Computer-aided Conceptual Design (CACD) systems are supposed to provide natural forms of expressing design intent. The creative power of the designer must not be hindered by difficult interaction procedures. Therefore, the designer’s natural way of communication must be the starting point for the interaction. Highly interactive system interfaces have to fulfil new requirements. A survey of requirements was composed from literature. In addition, a series of conceptualisation cases provided empirical data on interaction problems during conceptual design. The identified problems could be related to a number of requirements from the literature. Furthermore, additional requirements could be derived from the cases. The total set of requirements will be evaluated on several levels of abstraction, and implemented in a support system for the conceptual design of shape.

Cross Model Shape Reuse: Copying and Pasting of Freeform Features

This paper provides a systematic approach for copying and pasting of freeform features among existing models of design. Freeform feature as complex high-level shape entity enables a fast creation and modification of a geometric model in the context of both mechanical and aesthetic design. Copying and pasting of freeform feature can enhance not only the rapid shaping of the geometric model itself, but also the inheriting of design knowledge built in existing designs. In this paper definitions of freeform feature are reviewed and consummated. An analysis of parametric and topological relevancy of freeform feature is given in terms of copying operation and an elaboration of the reconstruction of freeform feature in a new geometric model regarding to pasting operation is presented. The reuse of freeform feature is discussed, and related algorithms are presented in detail.Copyright

Shape Knowledge Indexing Using Invariant Shape Code

Shape knowledge indexing is crucial in both design reuse and knowledge engineering, in which the pivot issue is to establish the unique representation of the invariant shape properties. Treating the shape of the region of interest as a surface signal, in this paper, a local shape-indexing scheme is developed by applying the affine invariant nature of the Fourier spectrum of the spatial shape distribution. The shape-coding scheme is theoretically proven being strictly invariant under affine transformations. A framework applying the invariant shape code in shape knowledge indexing is presented. Associated examples and the quantity analysis results are provided to justify the robustness, simplicity, and adaptability of the proposed shape knowledge-indexing scheme. Further, the proposed approach could be regarded as an alternative choice to represent local shape knowledge, especially for that of freeform features.Copyright

An Implementation of Intelligent CNC Machine Tools

Improving the machining efficiency of CNC machine tools by introducing intelligence is now gaining more attention from both researchers and entrepreneurs. Based on the assessment of existing strategy of intelligent machine tool design, an implementation and preliminary evaluation of an intelligent CNC lathe has been reported in this paper. Techniques discussed in this paper are expected to benefit CNC machine tool researchers and designers in terms of the development of intelligent CNC machine tools.

Exploring Conceptual Design Using a Clay-Based Wizard of Oz Technique

Abstract This paper describes the design and results of an explorative experiment done in the field of industrial design engineering. It extends the Wizard of Oz test technique by using clay as a feedback medium. The subject communicates with speech and gestures, the result is shown on a video screen. The experiment included 4 senior engineering students, each had to model four existing objects and then received a design assignment. The conclusions are that the method is applicable for simulating a multimodal design system, although there are some limitations regarding the direct manipulation of the artefact.

Enhancement of Interaction for Modelling in Conceptual Design

The prevailing Computer Aided Design/Engineering (CAD/CAE) systems are mainly for modelling, representation, simulation and evaluation purposes. However, future design support systems are expected to support more design tasks, including conceptual design activities. It can be expected that a wide range of new systems called Computer Aided Conceptual Design (CACD) systems will emerge and be used as front-end processors for traditional CAD systems. One of the conceptual design activities that should be supported by future CACD systems is shape conceptualisation. One of the main challenges of computer based shape conceptualisation lies in development of designer-shape interaction methods and tools that would provide the desirable support. This paper presents our research work in this area, which has so far been mainly on exploration of the potential technological solutions to interaction problems of modelling in conceptual design. We present desirable characteristic features for interaction in shape conceptualisation and describe a possible functionality of a CACD system.

Shape Terms in Different Languages

To improve interaction with CAD, we want to investigate the way people describe shape. Some research on this topic already exists, however, it can be expected that the way people describe shapes is different in different languages. A comparison was made between shape descriptions in English and Dutch. In general, the most frequently used description of a particular shape was the same in English and in Dutch. However, some shapes were described substantially different in both languages. About one third of the shapes was described differently; however,they contained words that could more or less be considered synonyms. A number of explanations of the different use of words are given, e.g. a word may be ambiguous in one language, or a word is considered rather formal in a particular language.

Approaches in Conceptual Shape Generation: Clay and CAD Modeling Compared

We compared the methods of modelers who modeled in clay and those who modeled in CAD. We gave special attention to the size and shape characteristics of the model, and to the differences in approach between individual modelers. Four modelers made three different objects in clay and four other modelers made the same three objects in CAD. As a measure of success of the modeling method, we used the quality of the generated model, based on a set of criteria. Generally, the overall appearance of the clay models was better than that of the CAD models. Individual modelers applied different approaches for the same shape, not only when using clay, but also during CAD modeling. The quality of the models varied greatly. We conclude that the most appropriate modeling method depends on the size and shape character of the model, and also of the preferences and skills of the subjects.

A Method to Improve Human-Computer Interaction for Shape Design, Based on Empirical Data

Human-computer interaction is often mainly based on the requirements of the software. However, for optimal communication between computer software and its users, the interaction should also fit to the way people work best. To be able to improve interaction with shape modeling software, a study was performed to investigate how people describe shape. The goal is to use the results of the study to adapt the interaction of shape modeling software in such a way that it better connects to the way people think and speak about shape. The study investigates which terms people use to describe shapes and shape operations. Furthermore, it investigates the differences and similarities among subjects who name shapes and shape operations. The study was done among Chinese bachelor students. For this research, a list was composed, containing descriptions of shapes and shape operations. All items in the list were then presented in pictures. The subjects had to name the shapes and shape operations that were depicted by the pictures. The paper describes the research method and shows how the results are analyzed. Furthermore, some first results are shown. Finally, possible implications for future human-computer interaction are discussed.

On the Stereoscopic Composition of Wide Baseline Stereo Pairs

Wide baseline cameras are broadly utilized in binocular vision systems, delivering depth information and stereoscopic images of the scene that are crucial both in virtual reality and in computer vision applications. However, due to the large distance between the two cameras, the stereoscopic composition of stereo pairs with wide baseline is hardly to fit the human eye parallax. In this paper, techniques and algorithms for the stereoscopic composition of wide baseline stereo pairs in binocular vision will be investigated. By incorporating the human parallax limitation, a novel algorithm being capable of adjusting the wide baseline stereo pairs to compose a high quality stereoscopic image will be formulated. The main idea behind the proposed algorithm is, by simulating the eyeball rotation, to shift the wide baseline stereo pairs closer to each other to fit the human parallax limit. This makes it possible for the wide baseline stereo pairs to be composed into a recognizable stereoscopic image in terms of human parallax with a minor cost of variation in the depth cue. In addition, the depth variations before and after the shifting of the stereo pairs are evaluated by conducting an error estimation. Examples are provided for the evaluation of the proposed algorithm. And the quality of the composed stereoscopic images proves that the proposed algorithm is both valid and effective.© 2009 ASME