Decisions made at the conceptual design stage have significant influence on factors such as costs, performance, reliability, safety and environmental impact of a product. However, knowledge of all the design requirements and constraints during this early phase of a product's life cycle is usually imprecise, approximate or unknown. Faced with such complexity, individual designers have restricted themselves to narrow, well-defined sub-tasks and as a result, progress in this area has been patchy and spasmodic. The purpose of this survey is to document the current state of research and development in this crucial design activity and in doing so, to identify avenues of fruitful exploration. In this paper, we provide a comparison of the advantages/disadvantages and limitations between the various techniques/tools and, where applicable, suggest possible future research directions.

Current research in the conceptual design of mechanical products

Shape grammars, utilizing function labels, are shown to be applicable to product design. A grammar that describes a language of coffeemakers is presented and shown to generate a large class of coff...

A Blend of Different Tastes: The Language of Coffeemakers:

The study of the design process, design theory and methodology has been a preoccupation of engineers, designers and researchers over the last four to five decades. As the end of this millenium is approached and with the renewed interest around the world in engineering design, it is fitting to examine the state of the art and current status of issues relating to design philosophies, theory and methodology. Over the last 40 years, many approaches to design have been put forward by various researchers, designers and engineers, both in academia and industry, on how design ought to and might be carried out. These proposals on design have tended towards what has come to be regarded as design philosophies, design models and design methods. The thesis of this paper is to discuss various aspects of generic research in design, within the above classifications in the light of the work that has been done in the last four decades. Discussions will focus on various definitions of design, design theory and methodology, ...

A Survey of Design Philosophies, Models, Methods and Systems

We introduce a real-time interactive visual editing paradigm for shape grammars, allowing the creation of rulebases from scratch without text file editing. In previous work, shape-grammar based procedural techniques were successfully applied to the creation of architectural models. However, those methods are text based, and may therefore be difficult to use for artists with little computer science background. Therefore the goal was to enable a visual work-flow combining the power of shape grammars with traditional modeling techniques. We extend previous shape grammar approaches by providing direct and persistent local control over the generated instances, avoiding the combinatorial explosion of grammar rules for modifications that should not affect all instances. The resulting visual editor is flexible: All elements of a complex state-of-the-art grammar can be created and modified visually.

/pdf/interactive-visual-editing-of-grammars-for-procedural-22dsvukaab.pdf

Interactive visual editing of grammars for procedural architecture

Developing objective measures for evaluating and measuring the complexity of design would facilitate (1) empirical studies that require the use of equivalent but different design problems, (2) the development of design curriculums, and (3) the comparison of computer aided design automation tools. This paper surveys and evaluates different approaches to defining complexity in design for the design problem, process, and product. Three fundamental aspects to complexity are identified, size, coupling, and solvability, and expanded with respect to the three elements of design, problem, process, and product. Alternative methods for measuring these characteristics of the design are based on computational, information, and traditional design views of complexity. A method of measuring size as it relates to complexity is proposed for measuring the information content of design. A second method is proposed for decomposing a graph-based representation of design that provides a measure of the interconnectedness as it relates to complexity. Finally, two methods are proposed for determining the solvability complexity of design based on the effort involved and the degree of freedom of design. These measures are developed specifically for parametric and geometric problems as found in the embodiment design, but these principles may be applied beyond this.

Mechanical Engineering Design Complexity Metrics: Size, Coupling, and Solvability

The authors present a methodology for human identification based on digital superimposition techniques. This methodology computes a fast, near optimal fit between a three-dimensional skull surface mesh and a two-dimensional digitized facial photograph. Since this is done digitally, (1) the photograph can be enhanced to reduce or eliminate motion blur, overexposure or underexposure, and out-of-focus distortions; (2) previous problems with skull/photograph scaling and alignment are minimized or eliminated; and (3) the photograph and skull can be numerically correlated. Two of several test cases produced from an implementation of this methodology are also presented.

A methodology for near-optimal computational superimposition of two-dimensional digital facial photographs and three-dimensional cranial surface meshes.

A number of two-dimensional (2D) and three-dimensional (3D) shape grammar interpreters have been developed over the years. In fact, 2D variants of such interpreters are now commonly assigned as classroom exercises. In this note, a 3D implementation is described based on a commercial solid modeling kernel and an associated functional language. A Scheme implementation of the approach is discussed and several examples are given.

Note on a Three-Dimensional Shape Grammar Interpreter

The study of languages of shape is rich and interesting. One can develop formal grammars whose languages are non-realizable shape (nonsense objects), as well as grammars whose languages are classes of realizable shape. This paper develops several graph-based multi-dimensional languages that are complete in the physical solids. Thus, realizable shape is a language.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0890060400002353

Formal graph languages of shape

Shape grammars offer a notationally rich representation for dealing with shapes defined over an algebra of points, lines, planes, and solids. Operations in the algebra are bound in subshape recognition and replacement, making them ideal candidates for design as formal solid modeling representations, and for manufacturing as shape-based feature recognizers. As well, given the topological hierarchy of the algebra of shapes, non-manifold modeling is clearly a fundamental part of shape grammars. Thus, one can work at the level of wireframe models, boundary models, and solid models. These characteristics make the shape grammars eminently suitable as a formal representation for both manifold and non-manifold representations of discrete shape.

A shape grammar for non-manifold modeling

Computational abstraction of engineering design leads to an elegant theory defining (1) the process of design as an abstract model of computability, the Turing machine; (2) the artifacts of design as enumerated strings from a (possibly multidimensional) grammar; and (3) design specifications or constraints as formal state changes that govern string enumeration. Using this theory, it is shown that engineering design is a computable function. A computational methodology based on the theory is then developed that can be described as a form follows function design paradigm.

Patrick A. Fitzhorn

Papers

A methodology for near-optimal computational superimposition of two-dimensional digital facial photographs and three-dimensional cranial surface meshes.

Note on a Three-Dimensional Shape Grammar Interpreter

Formal graph languages of shape

A shape grammar for non-manifold modeling

Engineering design is a computable function