• International Journal of CAD/CAM
• /
• v.9 no.1
• /
• pp.17-24
• /
• 2010

For several years, researchers have focused on improving the integration of the CAD, CAM and Analysis through a better communication between the various analysis tools. This tendency to integrate the CAD/Analysis and automation of the corresponding processes requires data sharing between the various tasks using an integrated product model. We are interested in this research orientation to CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results (deformed mesh). Because this problem is complex, it requires to be split into several complementary parts. This paper presents an original interoperability process between the CAD and CAE. This approach is based on a new technique of rebuilding the CAD surface model (Nurbs, Bezier, etc.) starting from triangulation (meshed surface) as a main step of the BREP solid model. In our work, the advantages of this approach are identified using a centrifugal pump example.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.5
• /
• pp.328-338
• /
• 2005

CAD systems are routinely used by designers for creating part geometries. Interfaces to CAE/CAM systems are also commonplace enabling the FEA-based design optimization and the rapid fabrication of the designed part. However, conventional CAD systems have thus far focused on objects with homogeneous interior. Two recent advances--use of heterogeneous objects such as Functionally Graded Materials (FGM) in parts and Layered Manufacturing Technology (LMT)--have brought to the forefront the need for CAD systems to support the creation of geometry as well as the graded material inside. We first describe the need and the components of such a CAD system for heterogeneous objects. A prototype CAD system is then described with one specific example (thermal barrier type FGM, pressure vessel) in order to illustrate the use of the implemented CAD system. The implemented system is manually integrated with FEA tools for optimal design. Our ongoing work involves the automation of the integration with FEA tools.

• Korean Journal of Computational Design and Engineering
• /
• v.6 no.4
• /
• pp.254-262
• /
• 2001

It is not possible to exchange parametric information of CAD (Computer Aided Design) models based on the current version of STEP (Standard leer the Exchange of Product model data). The design intent can be lost during the STEP transfer of CAD models. The ISO Parametrics Group has proposed the SMCH (Solid Model Construction History) schema in June 2000 that includes structures fur exchange of parametric information. This paper proposes the macro parametric approach that is intended to provide capabilities to transfer parametric information. In this approach, CAD models are exchanged in the form of macro files. The macro file contains user commands which are used in the modeling phase. To exchange CAD models using the macro parametric approach, modeling commands of commercial CAD systems are analyzed. Those commands are classified by the grouping method suggested by Bill Anderson. As a neutral file format, a standard modeling commands set has been defined. Mapping relations between the standard modeling commands set and the native modeling commands set of commercial CAD systems are defined.

• International Journal of CAD/CAM
• /
• v.2 no.1
• /
• pp.13-21
• /
• 2002

It is not possible to exchange parametric information of CAD models based on the current version of STEP. The design intent can be lost during the STEP transfer of CAD models. The Parametrics Group of ISO/TC184/SC4 has proposed the SMCH schema, which includes constructs for exchange of parametric information. This paper proposes a macro-parametric approach that is intended to provide capabilities to transfer parametric information including design intents. In this approach, CAD models are exchanged in the form of macro files. The macro file contains the history of user commands, which are used in the modeling phase. To exchange CAD models using the macro-parametric approach, the modeling commands of several commercial CAD systems are analyzed. Those commands are classified and a set of standard modeling commands has been defined. Mapping relations between the standard modeling commands and the native modeling commands of commercial CAD systems are defined. The scope of the current version is limited to parts modeling, not assemblies.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.19 no.2
• /
• pp.242-263
• /
• 1995

The study was to find out the current situation of supply and demand of apparel CAD systems in Korea. Also it was hoped to gather any valuable information about the current usage of apparel CAD systems for the development of the enhanced apparel CAD system. Three interviews were carried out for the study. The first interview with the importing agents was to find out the apparel CAD system's supplying situation. The second interview with the users of apparel CAD system was about the usage of the systems and related informations. The last interview was about the pattern making facilities, which was pointed out by the users to be the most inconvenient part of apparel CAD systems. The results of the survey were: 1. The supply and demand of apparel CAD systems is increasing. 2. The education, training, maintenance of the system should be improved by the supplier. 3. Apparel CAD systems are used for various production systems in the apparel industry. 4. 100% of the systems are utilized for pattern input and 89% of the systems are utilized for marker making. Only 15% of the systems are utilized in pattern making process, which 80% of the users realize to be computerized. 5. The most serious barrier to the better usage of the system is the communication with the system in foreign language. This barrier could be lifted when Korean apparel CAD system is developed.

• Proceedings of the ESK Conference
• /
• 1993.10a
• /
• pp.165-188
• /
• 1993

The study was to find out the current situation of supply and demand of apparel CAD systems in Korea. Also it was hoped to gather any valuable information about the curent usage of appared CAD systems for the development of the enhanced apparel CAD system. Three interviews were carried out for the study. The first interview with the importing agents was to find out the apparel CAD system's supplying situation. The second interview with the users of apparel CAD system was about the usage of the systems and related informations. The last interview was about the pattern making facilities, which was pointed out by the users to be the most inconvenient prat of apparel CAD systems. The results of the survey were:- 1. The supplu and demand of apparel CAD systems is increasing. 2. The education, training, maintenance of the system should be improved by the supplier. 3. Apparel CAD systems are used for various production systems in the apparel industry. 4. 100% of the systems are utilized for pattern input and 89% of the systems are utilized for marker making. Only 15% of the systems are utilized in pattern making process, which 80% of the users realize to be computerized. 5. The most serious barrier to the better usage of the system is the communication with the system in foreign language. This barrier could be lifted when Korean apparel CAD system is developed.

• International Journal of CAD/CAM
• /
• v.7 no.1
• /
• pp.1-10
• /
• 2007

The compression of CAD models is a key technology for realizing Internet-based collaborative product development because big model sizes often prohibit us to achieve a rapid product information transmission. Although there exist some algorithms for compressing discrete CAD models, original precise CAD models are focused on in this paper. Here, the characteristics of hierarchical structures in CAD models and the distribution of their redundant data are exploited for developing a novel data encoding method. In the method, different encoding rules are applied to different types of data. Geometric data is a major concern for reducing model sizes. For geometric data, the control points of B-spline curves and surfaces are compressed with the second-order predictions in a local coordinate system. Based on analysis to the distortion induced by quantization, an efficient method for computation of the distortion is provided. The results indicate that the data size of CAD models can be decreased efficiently after compressed with the proposed method.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2008.11a
• /
• pp.291-296
• /
• 2008

For the past two decades, 3D/4D CAD research has heel mainly focused on the design and construction phase of a facility life-cycle. However, there has been a general notion that the strength of 3D/4D CAD lends itself to other phases such as planning, operation and maintenance. In this research, a 3D/4D CAD model was generated in a commercial software platform. Then, the traditional 1:fe cycle facility management procedures are reviewed to, see any possible improvement opportunity with the 3D/4D CAD model as an example. A focus group interview, in conjuction with an extensive literature review, produced the list of area where 3D/4D CAD model could significantly benefit the traditional life cycle facility practices. Finally, a questionnaire-based survey was conducted with 155 respondents to statistically verify the feasibility of 3D/4D CAD for life cycle facility management.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2006.11a
• /
• pp.154-160
• /
• 2006

There wasn't very successful practice cases for the quantity take-off based on the CAD system since the CAD system is used in the construction industry more than 20 years in Korea. It was also not easy to use 3D CAD system in design management and cost management in the construction industry although 3D CAD system is very successful in the manufacturing industry for those areas recently. It is important to construct 3D libraries and to supply those libraries for the designers in time. Architectural work is a kind of creative work. So, Architects like to create their own model. Unlike the manufacturing industry, 3D CAD system can not be survived in the construction industry without new 3D objects supply in the right time. Moreover, the estimation system for 3D must support the schematic design phase, detailed design phase and construction design phase. The product called "Constructor" of Graphisoft consist of modeller, estimator and scheduler based on 3D model. We applied the system to a real project and compared the estimation result and we made a very successful case study.

• Korean Architects
• /
• no.6 s.219
• /
• pp.74-83
• /
• 1987

CAD시스템을 도입하여 활용하고 있는 필자의 경험을 토대로 하여 현재 CAD시스템의 도입을 검토하고 있거나 혹은 관심을 가지고 있는 설계사무실의 입장에 서서 결코 만만치 않은 가격의 CAD시스템을 어떻게 이해하고 활용할 것인가 하는 것을 중점적으로 고찰하였다. 지면사정상 깊이있는 이론적 설명은 배제하고 사무실에서 부딪히는 현실적인 문제를 위주로 기술하였으므로 경영하자 CAD책임자에게 특히 도움이 될 수 있었으면 한다.