Ammon Hepworth

Model Consistency and Conflict Resolution With Data Preservation in Multi-User Computer Aided Design

Simultaneous multi-user computer aided design (CAD) allows multiple designers to contribute to the same model at the same time. The resulting parallel design workflow shortens product development cycles. In a replicated, simultaneous multi-user CAD system, modeling data must be kept consistent between clients. This paper presents a method that keeps independent copies of the models in sync between distributed CAD clients. This is accomplished by enforcing modeling operations to occur in the same order on all the clients. In case of conflict, a resolution method preserves conflicting operations locally for later reuse or resolution by the user. These methods are implemented in a commercial CAD system which has been enhanced to enable simultaneous multi-user. Validation tests are run to demonstrate that the methods implemented ensure model consistency and resolve conflicts while preserving conflicting operation data.

Automated Conflict Avoidance in Multi-user CAD

The NSF Center for e-Design, Brigham Young University (BYU) site has re-architected Computer Aided Design (CAD) tools enabling multiple users to concurrently create, modify and view the same CAD part or assembly. This technology allows engineers, designers and manufacturing personnel to simultaneously contribute to the design of a part or assembly in real time, enabling parallel work environments within the CAD system. Such systems are only as robust as their methods for managing conflicts (i.e. simultaneous edits of the same feature by multiple users). A heavy-handed conflict prevention would limit collaborative freedom. This paper discusses an automated feature reservation method which prevents multiple users from simultaneously editing the same feature. The method is implemented in a commercial CAD system. Results show that this methodology prevents data inconsistency that results from feature/self conflicts. This system prevents CAD modeling conflicts, while providing an agile user experience within the collaborative environment.

Scalable Integration of Commercial File Types in Multi-User CAD

ABSTRACTCurrent commercial computer aided design (CAD) tools limit a parallel engineering design workflow by only allowing a single user in the CAD model at a time. The NSF Center for e-Design at BYU has recently developed multi-user CAD tools which enable a parallel design workflow by allowing multiple users to simultaneously contribute to the same CAD model in real time. The combined challenges of consistent distributed naming and robust interoperation with commercial file types have created scalability and usability issues for previous multi-user CAD implementations. This paper presents persistent naming methods and a file-based architecture that address these challenges. An implementation of these methods shows that multi-user design within commercial CAD is increasingly scalable.

Multi-User Computer-Aided Design and Engineering Software Applications

This chapter will introduce multi-user computer-aided engineering applications as a new paradigm for product development, considering past collaborative research and the emerging wave of cloud-based social and gaming tools. In a historical context, computer-aided design and engineering models have become much more complex since their inception in the middle of the twentieth century. However, the way design teams approach these models has, at least in one sense, not changed much; a given model can still only be accessed by one user at a time, despite the fact that the entire design team needs to evolve the model. Single user applications have become a productivity bottleneck and do not provide interfaces or architectures for simultaneous editing of models by a collaborative team. Single user applications convert any hope for process concurrency into a serial sequence of design activities. When the single user designer experiences difficulties, the process halts until the designer can reach out to other experts to resolve the problems, which usually requires some form of external collaboration. Unfortunately, single user applications are deficient when it comes to complex and globalized product development. The chapter herein will consider how multi-user architectures will change the single user paradigm from serial to simultaneously collaborative, promote new on-demand access methods like cloud serving, and bring long hoped for efficiencies to product development. We will investigate three research areas of importance to this emerging paradigm: (1) multi-user CAx architectures, including cloud serving; (2) multi-user CAx requirements; and (3) multi-user CAx standards. Of these three, architectures are most investigated, with numerous proof-of-concept prototypes, while requirements and standards, the least investigated, partially explain the reason for non-adoption and non-commercialization of this powerful new paradigm.

Collaborative Design Principles From Minecraft With Applications to Multi-User CAD

Real-time simultaneous multi-user (RSM) computer-aided design (CAD) is currently a major area of research and industry interest due to its potential to reduce design lead times and improve design quality through enhanced collaboration. Minecraft, a popular multi-player online game in which players use blocks to design structures, is of academic interest as a natural experiment in collaborative 3D design of very complex structures. Virtual teams of up to forty simultaneous designers have created city-scale models with total design times in the thousands of hours. Using observation and a survey of Minecraft users, we offer insights into how virtual design teams might effectively build, communicate, and manage projects in an RSM CAD design environment. The results suggest that RSM CAD will be useful and practical in an engineering setting with several simultaneous contributors. We also discuss the potential effects of RSM CAD on team organization, planning, design concurrency, communication, and mentoring.Copyright

Integrated, Synchronous Multi-User Design and Analysis

An integrated multi-user system for synchronous design and analysis improves collaboration and concurrent engineering across multiple engineering disciplines. This approach allows all members of a multidisciplinary team (i.e., a team made up of designers and structural analysts) to access the same shared model over a computer network and synchronously contribute to the model in real-time. Data for both design and analysis are directly based on the same mathematical representation of the geometry, eliminating the need for model translation between disciplines. All data are stored on a central server which allows simultaneous access by multiple users. Each user views and operates on the model in a way specific to his or her discipline. Updates to the shared model are seen in real-time. This system enables an enhanced parallel product development workflow, since users from multiple disciplines can simultaneously contribute to the same engineering model. A simple implementation of an integrated multi-user design and analysis system was developed to demonstrate this method. Preliminary results from two experiments suggest a reduction in the amount of time required to perform design and analysis operations when compared with traditional, single-user approaches. Future research is suggested.

Collaborative Design Principles From Minecraft With Applications to Multi-User Computer-Aided Design

Synchronous collaborative (“multi-user”) computer-aided design (CAD) is a current topic of academic and industry interest due to its potential to reduce design lead times and improve design quality through enhanced collaboration. Minecraft, a popular multiplayer online game in which players can use blocks to design structures, is of academic interest as a natural experiment in a collaborative 3D design of very complex structures. Virtual teams of up to 40 simultaneous designers have created city-scale models with total design times in the thousands of hours. Using observation and a survey of Minecraft users, we offer insights into how virtual design teams might effectively build, communicate, and manage projects in a multi-user CAD design environment. The results suggest that multi-user CAD will be useful and practical in an engineering setting with several simultaneous contributors. We also discuss the effects of multi-user CAD on team organization, planning, design concurrency, communication, and mentoring.

An integrated task management system to reduce semantic conflicts in multi-user computer-aided design

Simultaneous multi-user computer-aided design enables teams of designers to contribute simultaneously to the same model. As multiple users make contributions to the model, all users see additions from all other collaborators in real-time. However, without careful coordination, conflicts that violate the design intent of the model may occur. These are referred to as semantic conflicts and lead to redundant work by users. This article presents a method to reduce semantic conflicts through a task management system integrated directly into multi-user computer-aided design. Experiments were run that compare multi-user teams’ design modeling times with and without the integrated task management system. The results of these experiments show that the integrated task management system significantly reduces the time to complete design models by reducing semantic conflicts through enhanced organization and communication.

Enhancements for Improved Topological Entity Identification Performance in Multi-user CAD

ABSTRACTMulti-user CAD allows designers to simultaneously work on a model, allowing designs to be realized at a much faster rate than ever before. In a replicated, simultaneous multi-user CAD system, it is critical that models be consistent between clients. A major component of model consistency is ensuring references to topological objects be the same on all clients in the same part. Previous methods are inefficient for models with a large number of faces and edges. This paper presents enhancements over previous methods which more efficiently identify faces and edges through lazy naming as well as caching and normalizing topological entity data. The implementation and results of these enhancements show significant time savings compared to an eager naming method.

Semantic conflict reduction through automated feature reservation in multi-user computer-aided design

Commercial computer aided design (CAD) tools are single user, thus only allowing one user to contribute to a CAD model at a time. The NSF Center for e-Design, BYU site is developing multi-user plug-ins for commercial CAD systems to extend their functionality to allow multiple users to simultaneously contribute to a collaborative design model. One central issue in developing and working in a multi-user CAD system is handling conflicts that occur between users. Semantic conflicts occur when multiple users perform operations which violate the design intent of the model, adding waste to the overall design process. Previous work has shown how automated feature reservation avoids conflicts which lead to data inconsistency, but does not discuss how this helps reduce semantic conflicts. This paper will discuss the development of a mathematical model and the results of experiments which suggest that automated feature reservation reduces semantic conflicts in multi-user CAD modeling.