Layered shape grammars

In this article we propose a computer-aided conceptual design system to assist modelling at the early stages of design. More precisely, we address the problem of providing the designer with design alternatives that can be used as starting points of the design process. To guide the generation of such alternatives according to a given set of design requirements, the designer can express both visual knowledge in the form of basic geometric transformation rules, and also logic constraints that guide the modelling process. Our approach is based on the formalism of shape grammars, and supplements the basic algorithms with procedures that integrate logic design constraints and goals. Additionally, we introduce a layered scheme for shape grammars that can greatly reduce the computational cost of shape generation. Shape grammars, constraints, goals and layers can be handled through a graphic environment. We illustrate the functionalities of ShaDe through two use cases taken from the architectural design and video games domains, and also evaluate the performance of the system.     

A conceptual approach for the die structure design

A large number of decisions are made during the conceptual design stage which is characterized by a lack of complete geometric information. While existing CAD systems supporting the geometric aspects of design have had little impact at the conceptual design stage. To support the conceptual die design and the top–down design process, a new concept called conceptual assembly modeling framework (CAMF) is presented in this paper. Firstly, the framework employs the zigzag function-symbol mapping to implement the function design of the die. From the easily understood analytical results of the function-symbol mapping matrix, the designer can evaluate the quality of a proposed die concept. Secondly, a new method—logic assembly modeling is proposed using logic components in this framework to satisfy the characteristic of the conceptual die design. Representing shapes and spatial relations in logic can provide a natural, intuitive method of developing complete computer systems for reasoning about die construction design at the conceptual stage. The logic assembly which consists of logic components is an innovative representation that provides a natural link between the function design of the die and the detailed geometric design.     

Conceptual design, manufacturability evaluation and preliminary process planning using function-form relationships in stamped metal parts

A large number of design decisions are made during the conceptual design of a part. However, there are few representation and reasoning tools for decision support during conceptual design. The conceptual design stage is characterized by a lack of complete geometric information. Existing geometric modelers require complete geometric information, while a functional reasoning methodology using a <verb, noun > representation is typically too terse. In this paper, we present a new representation called sketching abstraction for conceptual design, using the function-form relations in a design. The functionally critical part of the geometry is presented using a set of functional features, while the rest of the geometry is abstracted as a set of linkages. Part functionality is correlated with the sketching abstraction using data structures called function-form matrices. The sketching abstraction is annotated using a set of primitives, and a set of grammar rules are used to extract canonical relationships between the functional features. The sketching abstraction can be used for extracting designs that are geometrically dissimilar but functionally similar, thus providing the designer with ideas for design alternatives. The sketching abstraction can also be used to carry out domain-dependent manufacturability evaluation checks. A further use of sketching abstractions is to initiate the development of a process plan for manufacturing. Sketching abstractions are related to the solid model of a part. Thus, this representation provides a link between pure functional and pure geometric representations. The domain of application is stamped metal parts. We present the part functionality and the features used in this domain. We also illustrate the use of sketching abstractions for conceptual design, manufacturability evaluation and preliminary process planning.     

BIM extension for the sustainability appraisal of conceptual steel design

Contemporary advancements in Information Technology and the efforts from various research initiatives in the AEC industry are showing evidence of progress with the emergence of building information modelling (BIM). BIM presents the opportunity of electronically modelling and managing the vast amount of information embedded in a building project, from its conception to end-of-life. Researchers have been looking at extensions to expand its scope. Sustainability is one such modelling extension that is in need of development. This is becoming pertinent for the structural engineer as recent design criteria have put great emphasis on the sustainability credentials in addition to the traditional criteria of structural integrity, constructability and cost. With the complexity of designs, there are now needs to provide decision support tools to aid in the assessment of the sustainability credentials of design solutions. Such tools would be most beneficial at the conceptual design stage so that sustainability is built into the design solution starting from its inception. The sustainability of buildings is related to life cycle and is measured using indicator-terms such as life cycle costing, ecological footprint and carbon footprint. This paper proposes a modelling framework combining these three indicators in providing sustainability assessments of alternative design solutions based on the economic and environmental sustainability pillars. It employs the principles of feature-based modelling to extract construction-specific information from product models for the purposes of sustainability analysis. A prototype system is implemented using .NET and linked to the BIM enabled software, Revit Structures™. The system appraises alternative design solutions using multi-criteria performance analysis. This work demonstrates that current process and data modelling techniques can be employed to model sustainability related information to inform decisions right from the early stages of structural design. It concludes that the utilized information modelling representations – in the form of a process model, implementation algorithms and object-based instantiations – can capture sustainability related information to inform decisions at the early stages of the structural design process.     

Reo + mCRL2 : A framework for model-checking dataflow in service compositions

The paradigm of service-oriented computing revolutionized the field of software engineering. According to this paradigm, new systems are composed of existing stand-alone services to support complex cross-organizational business processes. Correct communication of these services is not possible without a proper coordination mechanism. The Reo coordination language is a channel-based modeling language that introduces various types of channels and their composition rules. By composing Reo channels, one can specify Reo connectors that realize arbitrary complex behavioral protocols. Several formalisms have been introduced to give semantics to Reo. In their most basic form, they reflect service synchronization and dataflow constraints imposed by connectors. To ensure that the composed system behaves as intended, we need a wide range of automated verification tools to assist service composition designers. In this paper, we present our framework for the verification of Reo using the mCRL2{{\tt mCRL2}} toolset. We unify our previous work on mapping various semantic models for Reo, namely, constraint automata, timed constraint automata, coloring semantics and the newly developed action constraint automata, to the process algebraic specification language of mCRL2{{\tt mCRL2}}, address the correctness of this mapping, discuss tool support, and present a detailed example that illustrates the use of Reo empowered with mCRL2{{\tt mCRL2}} for the analysis of dataflow in service-based process models.     

定性立体形状表达和建模方法

概念设计在整个产品开发过程中的地位越来越重要,计算机辅助概念设计是计算机辅助设计的发展方向之一。传统的产品建模技术由于不能在产品开发的初期阶段很好地为产品的设计服务,因此有必要研究和开发面向产品概念设计的新的产品建模方法。本文介绍了一种基于领域和领域关系的定性立体形状表达方法和建模方法。该方法满足了概念设计对形状表达的要求,并能简化定性立体构筑过程。     

A meta-model approach for formal specification and consistent management of multi-LOD building models

The design of a building is a collaborative process among experts from multiple disciplines. Using Building Information Modeling (BIM), a model is developed through multiple refinement stages to satisfy various design and engineering requirements. Such refinements of geometric and semantic information are described as levels of development (LOD). Thus far, there is no method to explicitly define an LOD’s requirements nor to precisely specify the uncertainties involved. Furthermore, despite the insufficient information in the early design stages, a BIM model appears precise and certain, which can lead to false assumptions and model evaluations, for example, in the case of energy efficiency calculations or structural analyses. Hence, this paper presents a multi-LOD meta-model to explicitly describe an LOD’s requirements, incorporating the potential fuzziness of both, geometric and semantic information of individual elements. The explicitly defined fuzziness can be taken into account when applying simulations or analyses for assessing the performance of different building design variants. To support the continuous elaboration of a building from the conceptual to the detailed design stages, the multi-LOD model makes it possible to ensure the consistency of the geometric and semantic information as well as the topological coherence across the different LODs. The feasibility of the approach is demonstrated by its prototypical implementation as a web-server and user-interface, providing a means for managing and checking the exchange requirements both at the meta-level and for concrete building model instances. The paper is concluded with a case study of a real-world construction project that demonstrates the use of the meta-model to support model analysis and the decision-making process.     

一种面向方案设计的装配建模表示方法

ＣＡＤ系统对方案设计支持的关键是建立独立于几何细节而又表达的功构关系的装配模型,本文试图运用逻辑装配单元的定义来实现产品功能需求和结构表现间的有效关联,分别讨论了方案设计中功能描述和几何构形表示方式,形式化表达了方案设计的逻辑造型和装配建模过程,给出了支持自顶向下方案设计的装配模板定义,为方案设计的计算机辅助实现作了有益的尝试。     

A Bayesian analysis of the thermal challenge problem

A major question for the application of computer models is Does the computer model adequately represent reality? Viewing the computer models as a potentially biased representation of reality, Bayarri et al. [M. Bayarri, J. Berger, R. Paulo, J. Sacks, J. Cafeo, J. Cavendish, C. Lin, J. Tu, A framework for validation of computer models, Technometrics 49 (2) (2007) 138–154] develop the simulator assessment and validation engine (SAVE) method as a general framework for answering this question. In this paper, we apply the SAVE method to the challenge problem which involves a thermal computer model designed for certain devices. We develop a statement of confidence that the devices modeled can be applied in intended situations.     

A feature-based approach towards an integrated product model including conceptual design information

Due to the highly complex and informal data that has to be managed in the conceptual design this early design phase still lacks of suitable computer support. Furthermore, existing approaches towards a computer aided conceptual design are insufficiently integrated with the downstream applications of the product development process. The paper therefore introduces an approach towards a feature-based integrated product model that incorporates a feature-based representation scheme for capturing product semantics handled in the conceptual design phase and links early design with part and assembly modelling.     

Research on an active knowledge push service based on collaborative intent capture

The quality of a knowledge service influences the quality, efficiency and innovation of product conceptual design. Existing approaches lack intelligence and individuation when providing a knowledge retrieval service via rules and cases. In this paper, we propose a framework of an active knowledge service based on collaborative intent capture to assist product conceptual design. First, a collaborative intent capture model is constructed through the study of the expression and capture of collaborative intent; second, a framework and a process of active knowledge push based on collaborative intent capture are designed after analyzing the method of knowledge resources acquisition based on the constraint satisfaction theory. Finally, match algorithms for text content are studied. Based on the above research achievements, a prototype system of a collaborative design and active knowledge service platform (C-AKSP) has been developed for providing a knowledge service and assisting product conceptual design. An example, the conceptual design of a machine tool spindle system, is used to validate the proposed theories for the model, the framework and the algorithm. As a result, C-AKSP can provide a superior knowledge service that meets the designer's knowledge needs.     

Internet Based Collaborative Product Conceptual Design

Generation of Product Concept needs to give full play to the designers' innovative potential and collaborative work of experts in different fields. However, the collaborative innovative capabilities of geographically distributed designers are often limited and hindered by space and time. Therefore, on the basis of the requirements analysis of Internet based collaborative conceptual design and the research work we have done, this paper proposes the overall framework of supporting collaborative conceptual design on Internet. Based on this overall framework, the authors further put forward collaborative conceptual design process model that includes three stages: concept generation, concept communication and optimal product concept selection. At the end of the paper, the experiment environment of collaborative design is described. The overall framework and collaborative conceptual design process model proposed can take full advantage of Internet and give full play to experts' experiences and wisdom, so that the rapid development and innovative design of product can be provided with effectively and efficiently implemental mode and support on Internet.     

基于特征语义的变量设计

以前的变量设计技术用几何约束统一了不同尺寸的产品模型表示，但不能支持复杂的特征变异，本文引入特征语义几何元素及其约束实现了不同特征细节的统一表示，从而支持更广泛意义上的变量设计，文章论述了特征变异，设计过程，约束求解，系统分析与设计，以及原型系统研制中提出的新问题。     

Application of entity-based approach for unified representation of design alternatives for structural design

To support the design process fully from preliminary to detailed design stages in a natural way, a computer-integrated design system is needed. In early design stages more than one design alternatives are considered as possible solutions. The representation of design alternatives must be uniform and unbiased to be equally treated. In this study, an entity-based approach has been adopted to develop product and process models for representing design alternatives, which is more desirable for top–down design process because it allows high-level abstraction in representing design information and design activities. The entity-based approach has several benefits: (1) a unified representation of design alternatives; (2) a consistent development of product and process models based on the entity-based concepts; and (3) an easy integration of the product and process models. The work toward product and process models for structural design presented in this paper is a useful step toward integrated computer-aided design systems.     

Artist Space

Abstract

This paper addresses the process of patterning reconfigurable video narrative using architectural theory, through a case-study of practice-based research on the interactive, reconfigurable small-screen movie Gormenghast Explore. It focuses on the topography of cinematic narrative as architectural construction, refashioning Kevin Lynch's urban categories and Christian Norberg-Schulz's concept of place to support a design ontology for dramatic fictive narrativity. This architectural framework provides an effective representation for both navigable narrative content and 3D environment and interface.     

Integrated Structural–Architectural Design for Interactive Planning

Traditionally, building floor plans are designed by architects with their usability, functionality and architectural aesthetics in mind; however, the structural properties of the distribution of load‐bearing walls and columns are usually not taken into account at this stage. In this paper, we propose a novel approach for the design of architectural floor plans by integrating structural layout analysis directly into the planning process. In order to achieve this, we introduce a planning tool which interactively enforces checks for structural stability of the current design, and which on demand proposes how to stabilize it if necessary. Technically, our solution contains an interactive architectural modelling framework as well as a constrained optimization module where both are based on respective architectural rules. Using our tool, an architect can predict already in a very early planning stage whose designs are structurally sound such that later changes due to stability reasons can be prevented. We compare manually computed solutions with optimal results of our proposed automated design process in order to show how much our proposed system can help architects to improve the process of laying out structural models optimally.     

Interactive design exploration for constrained meshes

In architectural design, surface shapes are commonly subject to geometric constraints imposed by material, fabrication or assembly. Rationalization algorithms can convert a freeform design into a form feasible for production, but often require design modifications that might not comply with the design intent. In addition, they only offer limited support for exploring alternative feasible shapes, due to the high complexity of the optimization algorithm.We address these shortcomings and present a computational framework for interactive shape exploration of discrete geometric structures in the context of freeform architectural design. Our method is formulated as a mesh optimization subject to shape constraints. Our formulation can enforce soft constraints and hard constraints at the same time, and handles equality constraints and inequality constraints in a unified way. We propose a novel numerical solver that splits the optimization into a sequence of simple subproblems that can be solved efficiently and accurately.Based on this algorithm, we develop a system that allows the user to explore designs satisfying geometric constraints. Our system offers full control over the exploration process, by providing direct access to the specification of the design space. At the same time, the complexity of the underlying optimization is hidden from the user, who communicates with the system through intuitive interfaces.     

On technology for functional requirement-based reference design retrieval in engineering knowledge management

Engineering design is a knowledge-intensive process, and includes conceptual design, detailed design, engineering analysis, assembly design, process design, and performance evaluation. Each of these tasks involves various aspects of technical knowledge and experience. Whether this technical knowledge and experience can be effectively shared is key to increasing product development capability and quality, and also to reducing the duration and cost of the development cycle. Consequently, providing engineering designers various query methods for retrieving engineering knowledge is one of the most important tasks in engineering knowledge management.The study develops a technology for functional requirement-based reference design retrieval as a decision support mechanism, which can assist engineering designers to retrieve relevant design and associated knowledge for reference in conducting functional requirements of a product. This study involves the following tasks: (i) designing a functional requirement-based reference design retrieval process, (ii) developing techniques related to the technology for functional requirement-based reference design retrieval, and (iii) implementing a functional requirement-based reference design retrieval mechanism. The retrieval process includes the steps of functional requirement-based query, case searching and matching, and case ranking. The technology involves (i) a structured query model for functional requirements, (ii) an index structures for historical design cases, (iii) functional requirement-based case searching and matching mechanisms, (iv) a functional requirement-based case ranking mechanism, and (v) a case-based representation of designed entities. Finally, the experimental example with indexing and retrieving similar designed entities is conducted to demonstrate the proposed techniques worked efficiently.     

A functional approach to redesign

This paper describes a methodology to assist in the identification of possible conceptual design variants during redesign. The approach is based on functional reasoning and involves: (1) the structural and functional analysis of an existing design; (2) the production of abstract representations of functions and design entities using conceptual graphs; and (3) design interrogation based on a functional tree approach. The research reported in this paper also focuses on the definition and the representation of elementary mechanical functions. Extended Backus-Naur Form (EBNF) notations are used to structure in a computable form, the relevant information (or design knowledge) conceptualised in either the conceptual graphs or the functional trees. EBNF syntax is also used to formulate rules which aid the partial automation of the reasoning process. The EBNF notations can be mapped to any programming language. A diaphragm valve is used as a case study to demonstrate the approach.