scholarly journals A multi-user selective undo/redo approach for collaborative CAD systems

2014 ◽  
Vol 1 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Yuan Cheng ◽  
Fazhi He ◽  
Bin Xu ◽  
Soonhung Han ◽  
Xiantao Cai ◽  
...  
Keyword(s):  
Cad Model ◽  
Feature Combination ◽  
Collaborative Systems ◽  
Cad Systems ◽  
Cad System ◽  
Design Error ◽  
Engineering Design Process ◽  
Dependency Relationship ◽  
Cad Models ◽  
Remote Sites

Abstract The engineering design process is a creative process, and the designers must repeatedly apply Undo/Redo operations to modify CAD models to explore new solutions. Undo/Redo has become one of most important functions in interactive graphics and CAD systems. Undo/Redo in a collaborative CAD system is also very helpful for collaborative awareness among a group of cooperative designers to eliminate misunderstanding and to recover from design error. However, Undo/Redo in a collaborative CAD system is much more complicated. This is because a single erroneous operation is propagated to other remote sites, and operations are interleaved at different sites. This paper presents a multi-user selective Undo/Redo approach in full distributed collaborative CAD systems. We use site ID and State Vectors to locate the Undo/Redo target at each site. By analyzing the composition of the complex CAD model, a tree-like structure called Feature Combination Hierarchy is presented to describe the decomposition of a CAD model. Based on this structure, the dependency relationship among features is clarified. B-Rep re-evaluation is simplified with the assistance of the Feature Combination Hierarchy. It can be proven that the proposed Undo/Redo approach satisfies the intention preservation and consistency maintenance correctness criteria for collaborative systems.

Geometric Reasoning for the Coding of CAD Models

1995 ◽  
Author(s):  
A. Z. Qamhiyah ◽  
B. Benhabib ◽  
R. D. Venter
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Effective Means ◽  
Boundary Representation ◽  
Cad Model ◽  
Cad System ◽  
Cad Models ◽  
Form Features ◽  
Feature Based Design ◽  
Design Retrieval

Abstract Many of today’s concurrent product-development cycles depend on the utilization of intelligent Computer-Aided Design (CAD) systems. Thus, it would be essential to provide CAD users with effective means for interacting with the CAD system and its database. This paper addresses the development of a boundary-based coding procedure for CAD models. Coding the geometric and processing characteristics of objects, based on their CAD model representation, has been long recognized as an effective approach that allows convenient design retrieval on the one hand and process-planning automation on the other. Our work is based on the assumption that form features are recognizable and extractable from the CAD model by current feature-recognition, feature extraction and feature-based-design approaches. The coding procedure is applicable to the boundary representation of the object and its extracted form features.

scholarly journals Feature-based translation of CAD models with macro-parametric approach: issues of feature mapping, persistent naming, and constraint translation

2020 ◽  
Vol 7 (5) ◽  
pp. 603-614 ◽  
Author(s):  
Mutahar Safdar ◽  
Tahir Abbas Jauhar ◽  
Youngki Kim ◽  
Hanra Lee ◽  
Chiho Noh ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Parametric Approach ◽  
Model Data ◽  
Feature Mapping ◽  
Product Model ◽  
Cad Systems ◽  
Cad System ◽  
Cad Models ◽  
Feature Based ◽  
Aided Design

Abstract Feature-based translation of computer-aided design (CAD) models allows designers to preserve the modeling history as a series of modeling operations. Modeling operations or features contain information that is required to modify CAD models to create different variants. Conventional formats, including the standard for the exchange of product model data or the initial graphics exchange specification, cannot preserve design intent and only geometric models can be exchanged. As a result, it is not possible to modify these models after their exchange. Macro-parametric approach (MPA) is a method for exchanging feature-based CAD models among heterogeneous CAD systems. TransCAD, a CAD system for inter-CAD translation, is based on this approach. Translators based on MPA were implemented and tested for exchange between two commercial CAD systems. The issues found during the test rallies are reported and analyzed in this work. MPA can be further extended to remaining features and constraints for exchange between commercial CAD systems.

Interpretation of CAD models through neutral geometric knowledge

1990 ◽  
Vol 4 (1) ◽  
pp. 15-45 ◽  
Author(s):  
Bartholomew O. Nnaji ◽  
Tzong-Shyan Kang
Keyword(s):  
Point Of View ◽  
Feature Representation ◽  
Data Driven ◽  
Geometric Information ◽  
Cad Systems ◽  
Cad System ◽  
Standard Manner ◽  
Cad Models ◽  
Geometric Knowledge ◽  
Modelling Techniques

A generalized approach to fast interpretation of objects and their features has so far eluded researchers. In manufacturing, this interpretation can be approached from the vision point of view or from the CAD data perspective. Presently, CAD systems are widely used in several aspects of manufacturing production. It is therefore more efficient to use CAD data for object reasoning in manufacturing, especially when systems will eventually be data driven. Components can be modelled on a CAD system using various modelling techniques and the representation of their geometric information is still CAD system dependent. However, the advent of the Initial Graphics Exchange Specification (IGES) now makes it possible to represent CAD data in a neutral and standard manner.This paper describes a scheme for recognizing and representing features for CAD data extracted using the IGES interface. The concepts developed are based on graph-based feature representation, where features are represented by a set of faces as well as their topological adjacency.Strategies for classifying features and methods of decomposing a complicated feature into several simpler features for recognition purposes are discussed.

A Universal Feature Definition Frame for 3-D CAD Model Conversion

2013 ◽  
Vol 690-693 ◽  
pp. 2781-2786
Author(s):  
Chang Le Sun ◽  
Da Yong Ning ◽  
Wei Xiong ◽  
Hai Tao Wang
Keyword(s):  
Data Exchange ◽  
Target System ◽  
Cad Model ◽  
Important Research ◽  
General Outline ◽  
Cad Systems ◽  
Target Model ◽  
Universal Feature ◽  
Cad Models ◽  
Model Conversion

Data exchange between 3-D CAD systems has a very important research value both in theory and in application. This paper presents a general outline of a Universal Feature Definition (UFD) frame, which provides universal support for todays 3-D CAD systems. Through the medium of UFD feature, this frame can realize the conversion of 3-D CAD models from source system to target system according to API mapping. This CAD model conversion method may overcome the disadvantage of traditional geometric method that the target model is not editable. This frame also provides the conversion interface of user defined features, which is convenient for the user to customize the desired conversion process. The frame has been implemented between Catia and UG with successful results.

Concept of an Automatic Integration of Parts Measurement Data Into Feature-Based CAD Models

2018 ◽  
Author(s):  
Thiago Weber Martins ◽  
Lars Niemczik ◽  
Reiner Anderl
Keyword(s):  
Measurement Data ◽  
Product Development Process ◽  
Work Piece ◽  
Cad Model ◽  
3D Cad ◽  
Cad System ◽  
Target Values ◽  
Cad Models ◽  
Feature Based ◽  
Sheet Metal Profiles

This paper introduces a concept to integrate measurements data into feature-based 3D CAD models. The concept focuses on its application in the measurement of bifurcated sheet metal profiles. For that, an interface to read and import this data into the CAD system is developed. Since the measurement data is stored as a point cloud, further data processing (reverse engineering) is necessary to recreate the work piece shape in the CAD system. If the measured work piece model and the CAD model of the design piece are available, an automated comparison of the defined dimension takes place. The result is a notification in the CAD model indicating which dimension deviates from the target values. Use-cases are elaborated for integrating the concept in the product development process. To implement this concept, an experimental setup is built up consisting of a measurement system and 3D CAD system. The COPRA ProfileScan Desktop is used to measure the profile. Siemens NX 11 is the chosen CAD system. Based on this setup, the concept is validated on a manufactured profile.

Preserving Design Intent in Data Integration Between Virtual Prototyping and CAD Systems

1998 ◽  
Author(s):  
Sankar Jayaram ◽  
Uma Jayaram ◽  
Robert Kreitzer
Keyword(s):  
Information Needs ◽  
Virtual Prototyping ◽  
Typical Feature ◽  
Test Case ◽  
Cad Model ◽  
Original Design ◽  
Design Intent ◽  
Cad System ◽  
Cad Models ◽  
Assembly Constraints

Abstract State of the art CAD/CAM technology enables the capture of user design intent through the use of assembly constraints, features, parameters, etc. However, due to the large size of the CAD models, engineers are using other virtual prototyping methods for visualization and complete assembly analysis. Constraint and parameter information is lost in the transfer of models from the CAD system to the virtual prototyping systems. In virtual prototyping systems, users typically have tools to modify the location of an assembly component. In order to maintain model validity, procedures need to be developed to transfer these modifications back to the CAD system while maintaining the design intent of the original CAD user. In other words, how do we take information about changes to absolute or relative location and orientation of a component and transform this to updated constraint and parametric information in the original CAD model? In this paper, we address this need to update the constraints and parametric information of a CAD model based on location and orientation changes communicated from a virtual prototyping system. After analyzing and categorizing the assembly constraints in a typical feature-based CAD system, we propose a methodology to decide what information needs to be updated, and a procedure to update the information — all based on the original design intent captured in the constraints. The results of a test case to validate the methodology are also presented.

A Group Undo/Redo Mechanism to Preserve User Intention in Replicated Collaborative Modeling Systems

2009 ◽  
Author(s):  
Zhiyong Huang ◽  
Fazhi He ◽  
Xiantao Cai ◽  
Xiaoxia Li ◽  
Yuan Cheng
Keyword(s):  
Prototype System ◽  
User Intention ◽  
Cad Systems ◽  
Cad System ◽  
Collaborative Modeling ◽  
Local Site ◽  
Modeling Systems ◽  
Remote Sites ◽  
Special Challenge

Undo/redo mechanism is an important issue in interaction-centered CAD system. Since the design task is a creative process, the users of CAD systems have to use undo/redo mechanism to repeatly modify the CAD model in order to achieve a satisfied result. However, undo/redo mechanism is not an easy work even in standalone CAD systems. This is the reason why different commercial CAD systems are equipped with different level of undo/redo mechanism. Therefore, group undo/redo mechanism in collaborative system becomes a special challenge. This paper proposed a group undo/redo method in replicated collaborative modeling system. In our method, one user’s operation intention can be preserved in both local site and remote sites. The preservation is based on dependency relationship among users at different sites. The implementation of the Undo/Redo operation in both local site and remote site is described in detail respectively. The proposed approach has been tested in a prototype system with case study. The authors believe that this work represents the first attempt to address group undo/redo mechanism in collaborative CAD systems.

A Methodology for Building Up an Infrastructure of Haptically Enhanced Computer-Aided Design Systems

2008 ◽  
Vol 8 (4) ◽  
Author(s):  
Weihang Zhu
Keyword(s):  
Computer Aided Design ◽  
Force Feedback ◽  
Haptic Rendering ◽  
Haptic Interface ◽  
Cad Systems ◽  
3D Cad ◽  
Cad System ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

This paper presents an infrastructure that integrates a haptic interface into a mainstream computer-aided design (CAD) system. A haptic interface, by providing force feedback in human-computer interaction, can improve the working efficiency of CAD/computer-aided manufacturing (CAM) systems in a unique way. The full potential of the haptic technology is best realized when it is integrated effectively into the product development environment and process. For large manufacturing companies this means integration into a commercial CAD system (Stewart, et al., 1997, “Direct Integration of Haptic User Interface in CAD Systems,” ASME Dyn. Syst. Control Div., 61, pp. 93–99). Mainstream CAD systems typically use constructive solid geometry (CSG) and boundary representation (B-Rep) format as their native format, while internally they automatically maintain triangulated meshes for graphics display and for numerical evaluation tasks such as surface-surface intersection. In this paper, we propose to render a point-based haptic force feedback by leveraging built-in functions of the CAD systems. The burden of collision detection and haptic rendering computation is alleviated by using bounding spheres and an OpenGL feedback buffer. The major contribution of this paper is that we developed a sound structure and methodology for haptic interaction with native CAD models inside mainstream CAD systems. We did so by analyzing CAD application models and by examining haptic rendering algorithms. The technique enables the user to directly touch and manipulate native 3D CAD models in mainstream CAD systems with force/touch feedback. It lays the foundation for future tasks such as direct CAD model modification, dynamic simulation, and virtual assembly with the aid of a haptic interface. Hence, by integrating a haptic interface directly with mainstream CAD systems, the powerful built-in functions of CAD systems can be leveraged and enhanced to realize more agile 3D CAD design and evaluation.

Reorganizing CAD Assembly Models (as-Designed) for Manufacturing Simulations and Planning (as-Built)

2004 ◽  
Vol 4 (2) ◽  
pp. 98-108 ◽  
Author(s):  
Uma Jayaram ◽  
YoungJun Kim ◽  
Sankar Jayaram ◽  
Venkata K. Jandhyala ◽  
Tatsuki Mitsui
Keyword(s):  
Hybrid Method ◽  
Assembly Planning ◽  
Cad Model ◽  
Assembly Model ◽  
Assembly Sequence ◽  
Cad Systems ◽  
Cad System ◽  
Planning Tools ◽  
Assembly Constraints ◽  
Assembly Models

A CAD assembly model is a collection of components, comprised recursively of various levels of individual parts and sub-assembly models. Although the overall geometry in the CAD assembly model accurately represents the final finished product, this model is often meaningless from a manufacturing planning and simulation point of view. The grouping of the components into sub-assemblies and the assembly sequence implied by the CAD model does not accurately represent the manufacturing/assembly sequence or process. Reordering, regrouping, and modifying existing sub-assemblies, or creating new sub-assemblies in the CAD model may be needed to ensure this correspondence for simulation or assembly planning tools that derive the manufacturing sequence directly from the CAD system. Although this task can be performed using the existing functionality of the CAD system, it quickly becomes unwieldy for large industry-grade models due to the assembly constraints and relationships in place during the model creation. In industry today, there are several digital mockup and assembly planning tools that greatly outstrip the ability of CAD systems in loading complete models and creating assembly plans. Methods to organize the CAD model assembly quickly and easily for use in these systems, and to record the “as manufactured” assembly in the CAD data format are needed to close the loop and ease the transfer, storage, and maintenance of model data between the CAD systems, PDM systems, and these new age planning and mockup systems. In this paper, a new hybrid method is proposed to provide this functionality. Of key significance is the fact that using this approach, polygonal representations of any new or modified sub-assemblies designated in the reorganized hierarchy can be produced and that the original constraints used in the original assembly are transformed in a consistent manner to the new components. In addition, corresponding property files for the new components can be created for use in the assembly planning tool. In order to validate this hybrid approach, the time required to rearrange the assembly hierarchy and output the required information using both methods are compared–1) the traditional method using the CAD system alone, and 2) the new hybrid system. A statistical analysis using three treatment factors indicates that if the number of components is more than 15, then it is far more efficient to use the hybrid method over the CAD system by itself. This hybrid method implementation has now been used very successfully in virtual assembly simulations of many industry models, some with several hundred components, provided by various industry partners.

Haptic Guided Rigid Body Dynamics Study for Virtual Assembly in Mainstream CAD Systems

2007 ◽  
Author(s):  
Weihang Zhu
Keyword(s):  
Computer Aided Design ◽  
Virtual Assembly ◽  
Rigid Body Dynamics ◽  
Dynamics Simulation ◽  
Haptic Interface ◽  
Cad Systems ◽  
Cad System ◽  
Computer Aided ◽  
Cad Models ◽  
Aided Design

This paper presents our exploration in Haptic-guided Dynamics Simulation in a mainstream Computer-aided Design (CAD) System. Haptic interface, by providing force feedback in human-computer interaction, can improve the working efficiency of CAD/CAM (Computer-aided Design and Manufacturing) systems in a unique way. The full potential of the haptic technology is best realized when it is integrated effectively into the product development environment and process. For large manufacturing companies this means integration into a commercial CAD system [Stewart 1997]. Built on our past foundation work on an infrastructure of haptically enhanced CAD system [Zhu 2006], this research continues to explore the algorithms for dynamics simulation guided with haptic interface. This is fundamental to other tasks such as Virtual Assembly and Digital Mock-up. The research follows a modular haptic rendering algorithm for stable and transparent 6-DOF manipulation as presented in [Otaduy 2006], with improvements by leveraging the built-in CAD system functions and third party Dynamics Engines. The native CAD models are converted to triangulated meshes which are used in object-object collision detection and dynamics response computation. The major contribution of this paper is that we have developed a feasible methodology for haptic-guided dynamic interactions among CAD models inside mainstream CAD systems. It lays the foundation for future tasks such as direct CAD model modification and virtual assembly with the aid of haptic interface.

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