• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.107-114
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• 2004

This paper represents the application of the 3D CAD Model data for 4D simulation and quantity estimation. These support the effective and practical use of 4D CAD model. By using and manipulating the 3D CAD model information, scheduling and quantity estimation could be developed more quickly and effectively. So the 3D CAD model information is made use of not only drawing a blueprint but also playing an important part of data integration platform. The scheduling module sets up the schedule generation logic that consists of period, priority of element arrangement, and time lag of floor placement. It sorts the working items as a priority of working process. And the quantity estimation module queries the material quantity of the structural elements according to the scheduling conditions. These two modules are developed using the 3D CAD model information and assist the function of 4D CAD model.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.579-586
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• 2009

4D simulation integrates the 3 dimensional model of a building with the construction schedule, and it leads to the possibility of virtually checking the construction process and the building itself in advance. However, the existing problem of 4D simulation is the difference between the demands of architects, engineers, and construction site workers in 4D simulation. This study suggests the possible way to enhance the availability of 4D simulation, considering more the practical demands from the construction site. In order to conduct this study, we build a 3D BIM model of a business-residential complex and link the model with the pre-defined construction schedule in order to make a 4D simulation. This study concludes with the optimized 4D simulation methodology based on BIM model considering the demands in perspective of the construction site. It would contribute to the harmonic collaboration among architects, engineers, and labors in the construction site when using 4D simulation based on BIM model.

• Journal of Computational Design and Engineering
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• v.1 no.2
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• pp.96-102
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• 2014

In the field of design and manufacturing, there are many problems with managing dynamic states of three-dimensional (3D) objects. In order to solve these problems, the four-dimensional (4D) mesh model and its modeling system have been proposed. The 4D mesh model is defined as a 4D object model that is bounded by tetrahedral cells, and can represent spatio-temporal changes of a 3D object continuously. The 4D mesh model helps to solve dynamic problems of 3D models as geometric problems. However, the construction of the 4D mesh model is limited on the time-series 3D voxel data based method. This method is memory-hogging and requires much computing time. In this research, we propose a new method of constructing the 4D mesh model that derives from the 3D mesh model with continuous rigid body movement. This method is realized by making a swept shape of a 3D mesh model in the fourth dimension and its tetrahedralization. Here, the rigid body movement is a screwed movement, which is a combination of translational and rotational movement.

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.33-44
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• 2022

The simulation function by the 4D system is a representative BIM function in the construction stage. For the 4D simulation, schedule information for each activity must be created and then linked with the 3D model. Since the 3D model created in the design stage does not consider schedule information, there are practical difficulties in the process of creating schedule information for application to the construction stage and linking the 3D model. In this study, after extracting the schedule information of the construction stage using the HDBSCAN algorithm from the 3D model in the design stage, authors propose a methodology for automatically generating schedule information by identifying precedence and sequencing relationships by applying the topological alignment algorithm. Since the generated schedule information is created based on the 3D model, it can be used as information that is automatically linked by the common parameters between the schedule and the 3D model in the 4D system, and the practical utility of the 4D system can be increased. The proposed methodology was applied to the four bridge projects to confirm the schedule information generation, and applied to the 4D system to confirm the simplification of the link process between schedule and 3D model.

• Journal of Technologic Dentistry
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• v.41 no.4
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• pp.287-293
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• 2019

Purpose: To evaluate the accuracy of the 3D printed die models and to investigate its clinical applicability. Methods: Stone die models were fabricated from conventional impressions(stone die model; SDM, n=7). 3D virtual models obtained from the digital impressions were manufactured as a 3D printed die models using a 3D printer(3D printed die models;3DM, n=7). Reference model, stone die models and 3D printed die models were scanned with a reference scanner. All dies model dataset were superimposed with the reference model file by the "Best fit alignment" method using 3D analysis software. Statistical analysis was performed using the independent t-test and 2-way ANOVA (α=.05). Results: The RMS value of the 3D printed die model was significantly larger than the RMS value of the stone die model (P<.001). As a result of 2-way ANOVA, significant differences were found between the model group (P<.001) and the part (P<.001), and their interaction effects (P<.001). Conclusion: The 3D printed die model showed lower accuracy than the stone die model. Therefore, it is necessary to further improve the performance of 3D printer in order to apply the 3D printed model in prosthodontics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.181-189
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• 2021

In order to increase the practical usability of the virtual reality(VR)-based BIM object in the construction site, the difference between the virtual image and the real image should be resolved, and when it is applied to the construction schedule management function, it is necessary to reduce the image gap between the virtual completion and the actual completion. In this study, in order to solve this problem, a prototype of 4D model is developed in which augmented reality (AR) and 3D printing technologies are linked, and the practical usability of a 4D model linked with two technologies is verified. When a schedule simulation is implemented by combining a three-dimensional output and an AR object, it is possible to provide more intuitive information as a tangible image-based schedule information when compared to a simple VR-based 4D model. In this study, a methodology and system development of an AR implementation system in which subsequent activities are simulated in 4D model using markers on 3D printing outputs are attempted.

• Journal of KIBIM
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• v.4 no.3
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• pp.1-9
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• 2014

As BIM application continues to increase in civil engineering, in this study, 3D information model for RC(Reinforced Concrete) bridge pylon was developed and verified its effectiveness at the structural-design stage. To define 3D information model of RC A-Type pylon, characteristics of pylon were analyzed and 3D model structure was constructed. The 3D information model, one of the core product of BIM, manages all information generated during all life-cycle of a structure and consequently maximizes the efficiency of utilizing information. Also, this study proposes interface module between input data in structural analysis and 3D model of RC pylon. The module can create the input data for non-linear structural analysis. It is essential to study on method of developing 3D information model and propose a structural analysis model by utilizing 3D model for the effective use of BIM techniques in construction industry. The results of this study can be used as the base data for developing the 3D information model of RC pylon in the structural analysis field.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.559-562
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• 2006

Existing 4D systems are using the 1:1 link system that directly links a schedule and a 3D model object. But considering that plant facility includes various kinds of schedule and 3D model object, this study suggests an improved link methodology of multi-selected objects and two-way link system for minimizing link errors which generated in case of multi-selected objects. For the link system, this study introduces a new concept called as interface board. Interface board can be used as an information center for representing all information of link items in the current project. It may be expected that 4D model can build an effective and rapid link system of plant project by this new approach.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.585-588
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• 2003

This study attempts to develop a skeleton model to link construction schedule and 3D object for drawings in 4D system. Generally, the construction schedule and 3D object can be linked in 4D system by imported files which are made in specific S/Ws such as CAD S/W and scheduling S/W. Those methods have a difficulties for operating 4D data because extra work needs to link 4D data for each activity. This study develops a 4D model which the 4D data can be self-generated within the system. The suggested model can reduce the initial input data for new project by integrating schedule and 3D object in 4D system.

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