Internet-Based Concurrent Engineering: An Interactive 3D System With Markup

Although Concurrent Engineering can offer substantial benefits, and hence many companies take a strong interest in the collaborative approach, it is not yet clear how it can best be implemented, particularly for a geographically distributed Concurrent Engineering team that may be using a disparate range of computer systems. The recent rise in the number connected to the Internet would offer the possibility of using Internet standards to allow for collaboration over the Internet. Central to the use of Internet standards for Concurrent Engineering is the key area of transmitting and viewing CAD and engineering information, and of communication between team members. This paper is concerned with addressing this issue and describes the how 3D CAD files can be viewed, and engineering information exchanged, by geographically distributed team members in an interactive manner using Internet standards. In particular this paper is concerned with the issue of storing STEP data so that it can be retrieved efficiently, how this data can be converted from STEP data to the Virtual Reality Modeling Language (VRML) to allow the product to be viewed in interactive 3-D on a wide number of platforms using the Internet, and is concerned with the issue of how team members can markup the VRML worlds, with other team members being able to examine the markup comments of others. An algorithm for converting STEP data to VRML is described and an overview of the implementation of this approach, in a system called CyberView, is given. The result of this is that users from disparate functions, on a wide variety of platforms, can view products in interactive 3-D through the Internet, can comment on aspects of the design, and can examine the markup comments of other team members on particular aspects of the design. Such an approach offers the promise of improved communication and hence for enhancing the product development process.

A Temporal Process Specification Language for Virtual Manufacturing Engineering

A process specification language is being developed for virtual manufacturing that provides a structured portable definition of a given manufacturing process as well as the ability to specify the temporal relationships between individual operation steps that compose a process. Based on the concepts embodied in markup languages such as HTML, SGML and XML, a portable process definition structure is defined. This structure provides a template from which virtual process specifications can be created. Subsequently, these structures can be exchanged between development environments for virtual process engineering and the actualized manufacturing facilities where processes are implemented. In addition, dependencies in time between the operation steps of a process such as common start times and operation serialization can be represented to allow for a complete specification of temporal behavior of a given manufacturing process. By providing this explicit mechanism for representing temporal constraints, a virtual manufacturing process can be viewed and utilized both in a localized application on a single virtual factory floor as well as distributed across multiple, interlinked virtual environments.

Features and Constraints in Architectural Design

The concepts of the experimental design system that are discussed are feature modeling and geometrical constraints. The main technique for creating the user environment is Virtual Reality. Feature modeling forms the basis for managing the design data. To start with, data storage is implemented in a Relational Data Base Management System. Along with this a (traditional) interface is developed for managing the data. Data management consists of feature type creation and feature type instancing. Features are used to define building elements, their relationships and additional constraints. Apart from the design data, geometrical data are stored. The system contains a library of parameterized geometrical objects which format is in coherence with the geometrical modeling environment (VR). Possible design solutions can be limited using geometrical constraints. Specifying connection types between building elements result in a set of solutions for the position of the bounding boxes of the building elements in space.

Some Comments on the Differential Model of Hysteresis

The differential model of hysteresis has found general acceptance in computational mechanics. Shapes of hysteresis loops generated by the model depend on both the loop parameters and external excitation. In this paper, sensitivity of the differential model to various constituent parameters is studied. A more robust model of hysteresis can be constructed if sensitivity to loop parameters and excitation can be better understood.

Internet-Based Delivery of CAD/CAM Capability: An Industry Case Study

This paper presents a case study in the use of the Internet as a medium for exchange of information and delivery of computer-aided design and computer-aided manufacturing (CAD/CAM) capability. The case study describes a collaboration among researchers and staff at the National Institute of Standards and Technology (NIST), and Thar Designs, Inc., a small business in Pittsburgh, PA that designs and sells high-pressure fluid pumps. The objective of this case study is to identify the needs of small businesses in engineering industry in the area of Internet-based CAD/CAM services. The Internet-based interaction performed in this study encompassed various stages in an iterative product development process, consisting of design, data exchange, manufacturability analysis, and fabrication of a prototype.

Support of Disassembly / Reassembly Evaluation Within Total Life Cycle Modeling Through Feature Neighborhoods

Current research trends are extending from partially integrated product and process modeling to life cycle modeling, in order to provide a framework and methodologies based on a holistic approach for the support of sustainable product development. Within given scope we are interested to investigate, if feature technology, introduced in the late seventies and developed over the paste twenty years provides the potential, if further enhanced, to be used as a means to provide basic integration for geometry related processes and models over different product life cycle stages. In a first approach, feature neighborhoods are developed and introduced as an extension, to foster evaluation of disassembly / reassembly on grounds of feature-based product descriptions. An attempt to support product maintenance and material recycling within life cycle modeling while investigating structural dimension and limits of improved feature models as a means of geometry-based model integration.

A Virtual Prototyping System for Design for Assembly, Disassembly, and Service

Design for the life cycle practices enable the improvement of a product’s recycling, disassembly, and service characteristics, to name a few. In this paper, an approach to virtual prototyping is presented that supports product Design For Assembly, Disassembly, and Service (DFADS). The VP-DFADS system enables a designer to construct a product model, to interactively simulate an assembly, disassembly, or service process for that product, and to formulate and solve a simultaneous product/process design problem. Specific research objectives underlying this project include a reduction in VP model construction times, an improvement in information with which designers make DFADS decisions, and the development of a design synthesis method for DFADS. Although automated reasoning and synthesis technologies are outlined, the emphasis in this paper is on the integration of these technologies into the VP-DFADS system and on the usage of the system in supporting DFADS decisions. An application of the VP-DFADS system to automotive center console design illustrates the potential usefulness of the VP-DFADS approach.

Formation of Part Families for Shared Setups Generation in Sheet Metal Bending

Sheet metal bending press-brakes can be setup to produce more than one type of parts without requiring a setup change. To exploit this flexibility, we need setup planning techniques to generate press-brake setups that can be shared among many different parts. In this paper, we describe an algorithm which partitions a given set of parts into setup compatible part families which can be produced on the same setup. Our algorithm is based on a two step approach. The first step is to identify setup constraints for each individual part. The second step is to form setup-compatible part families based on the compatibility of setup constraints. We expect that by producing many different types of parts on the same setup, we can significantly reduce the required number of setups and enable cost effective small batch manufacturing.

Creating and Managing Virtual Menus in Immersive Environments

A 3D menu, also called a virtual menu, is now an accepted method of interaction between the user and the computer in an immersive environment. It adds functionality and allows interactions that are usually difficult to specify through direct interaction. We present the design and methodology of a support system for 3D menu creation and interaction in an immersive environment. Three kinds of virtual menus are supported — a paddle, a static billboard, and a dynamic billboard. These are distinguished by different spatial presentation and interaction paradigms in the virtual environment. The integration of the support system into an immersive environment is presented in the context of engineering applications research at Washington State University. Problems encountered and future planned enhancements are also examined. A clean separation between the virtual menu support system and the application in which the virtual menu will be created and displayed has been maintained.

A Bi-Directional Reflectance Function for Woven Textiles

This paper presents a novel bi-directional reflectance function for woven textile substrates. The new reflectance function models a broad class of woven substrates, including substrates with significant anisotropic reflectance. Isotropic behavior is handled as a special case of the anisotropic model. The new model recognizes fiber surface properties, thread geometry, and weave geometry. Experimental reflectance data is presented.