• Journal of KIBIM
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• v.4 no.4
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• pp.13-23
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• 2014

After being introduced, Building Information Modeling (BIM) has been actively applied to the cost estimation of construction projects, and various studies on BIM based quantity take-off have been carried out. In practice, however, these calculations take considerable time, because BIM based quantity take-off is further conducted along with 2D-based quantity take-off. Studies on the quantity take-off using BIM spatial objects have been carried out on early stages of projects, but how this method differs from the existing quantity take-off method and how accurate it is in comparison have rarely been verified. Therefore, by comparing 2D based quantities with quantities through BIM spatial objects, this study analyzed the accuracy of quantity take-off using BIM spatial objects. To this end, the properties of BIM spatial objects and quantity calculable spatial types were analyzed, and existing 2D-based quantities and quantities extracted from BIM spatial objects were compared through a case study. As a result, the quantity of spatial objects found to be more by about 7.13% in 0.05% and therefore, this difference should be considered during quantity take-off using BIM spatial objects. Through the results of this study, we can improve the accuracy of quantity take-off using BIM spatial objects in the early stage of a construction project.

• Journal of KIBIM
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• v.8 no.1
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• pp.56-62
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• 2018

There exists no precedented case of quantity take-off, using parametric modeling, from BIM-based irregular structures. Civil 3D provides earthwork quantity take-off based on surface modeling. Generally, designers should enter data into the specification additionally after extracting quantity estimation from earthwork modeling design. The objective of this report is to suggest the method from quantity take-off to specification of BIM-based earthwork quantities. We intend to investigate earthwork take-off method by Civil3D and explain why parametric information extraction is required for quantity estimation and specification and how information of earthwork quantity based on solid and surface modeling is connected to open quantity take-off module. It is highly expected that this suggestion would be the practical methodology of earthwork quantity take-off and specification in the field of civil engineering.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.73-74
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• 2023

The purpose of this study is to derive the cause of the quantity difference and present the considerations when take-off rebar quantity based on BIM model by comparing the quantity of rebar based on BIM model with 2D drawing. This research was limited to take-off the quantity of rebars in the building frame work, and after take-off the quantity of rebars by 3D modeling the 2D drawing of the target building with Revit, the quantity difference was compared with 2D-based software. Therefore, when take-off the quantity of rebars based on the BIM model, instead of take-off the existing 2D-based quantity premium proportion, according to general structural consider development length, lap splice length, covering thickness, reinforcing bars and spacing. In the future, this study is expected to contribute to improving the accuracy of BIM-based frame construction quantity take-off.

• Journal of KIBIM
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• v.3 no.2
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• pp.1-9
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• 2013

Currently, various studies and applications related BIM based quantity take-off have been attempted, because of the accuracy of cost estimating and reliability by using the BIM model information in automatical calculation. Finishing works that have a large number of various types and materials need the higher accuracy and reliability on the BIM-based quantity take-off. Therefore, this study compared and analyzed 2D and 3D based quantity through Test-bed and determine the cause of the quantity difference. This verified the accuracy and efficiency in the BIM-based quantity take-off for finishing works. Also this study has been proposed opinions for calculating the exact BIM-based quantity take-off.

• Korean Journal of Computational Design and Engineering
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• v.20 no.2
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• pp.182-192
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• 2015

In recent years, numerous studies have attempted to extract quantity data by using Building Information Modeling (BIM). In terms of open-BIM based quantity take-off at the early design stage, only few studies were conducted in the field of cost engineering. A lack of compatibility of open BIM for information exchange is postulated as the cause. The Industry Foundation Classes (IFC) extension model has been developed to accommodate the interoperability with quantity take-off software. Improvement of open BIM for quantity take-off needs exchange requirements and model guidelines. For this purpose, the quantity data of IFC models were analyzed using BIM analysis tools. This paper also provides a proposal of requirements on open BIM based quantity take-off at the early design stage. Further this study have been develop the interface system for open BIM based quantity take-off requirements with the results on this study.

• Journal of the Korea Institute of Building Construction
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• v.24 no.5
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• pp.607-618
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• 2024

With the growing adoption of Building Information Modeling(BIM), many studies on BIM-based quantity take-off are being conducted. However, the absence of standardized quantity take-off protocols for BIM-based methods has led to a decline in accuracy. This study aimed to compare quantity take-off results from 3D models with those derived from traditional 2D-based quantity take-off methods and modeling approaches, specifically for finishing work, and to identify the underlying causes of any discrepancies. The analysis revealed significant variations in the quantities of walls, floors, and ceilings, with walls exhibiting the largest deviation. The primary cause of these discrepancies was that when interior and exterior surfaces were modeled as a single composite object, it became impossible to accurately set the height of individual finishing materials, resulting in overestimations of the quantities. Consequently, the study demonstrated that modeling interior and exterior components as separate composite objects in 3D models can significantly reduce quantity take-off discrepancies. Moving forward, the establishment of precise quantity take-off standards through additional case studies will be crucial for improving cost management in BIM applications.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.92-93
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• 2019

Estimates based on BIM makes it possible to perform from quantity take-off to construction cost estimates by using model, which is made in the phase of design and construction. As the BIM models are made up of the units of element, there an advantage of the automative quantity take-off, if the correction or change of element occurs. Work items, not included in the elements of the BIM model, are excepted from bill of quantity. Level of detail(LoD) of the BIM model can be improved for detailed estimates, but an excessive modeling for estimates is inefficient. This study presents the measure for selection and quantity take-off of work items, those are not expressed in the BIM model. The proposed method avoids the creation of excessive BIM Models and enables quantity take-off in conjunction with the element.

• Korean Journal of Construction Engineering and Management
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• v.14 no.1
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• pp.12-22
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• 2013

Construction industry throughout the construction projects life cycle using BIM is able to manage information. Among them, BIM-based quantity take-off is directly connected to the data of the construction business as an important management element that is essential for one of the management factors of feasibility study and economic analysis. In addition, the result of BIM-based quantity take-off can be varied depending on modeler, so the exact guideline for BIM modeling is necessary. The BIM-based quantity take-off in terms of reliability and accuracy of the information is very important. Therefore, this study verified the BIM modeling of the apartment interior materials using both separate object and composite object was validated the quantitative comparison of the difference in BIM-based quantity take-off for accuracy & reliability judgment of BIM-based quantity take-off and realistic & desirable suggestion of BIM modeling way. As the result of this study, it is preferable to model various interior materials to use separate object for the purpose of correct BIM-based quantity take-off, but the realistic way of the BIM modeling using both separate object and composite object jointly was verified in order to judge BIM-based quantity take-off in terms of work productivity.

• Architectural research
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• v.15 no.2
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• pp.103-109
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• 2013

Various types of building information should be linked to 3D model objects for their effective use by stakeholders. Because Building Information Modeling (BIM) based on 3D is used by different stakeholders, the created BIM need standard guidelines for each purpose, as, for example, for quantity take-off. Thus, this study was conducted to propose guidelines for BIM modeling for quantity take-off in the framework, especially, in the concrete and form. The proposed guidelines adopted each element of the BIM model based on an analysis of the problem of the general BIM model. Moreover, the usability and accuracy of the reinforced structure modeling guidelines were verified by comparing the quantity of the commercial estimation software and the modeling quantity using the proposed modeling guidelines.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.79-92
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• 2011

Quantity take-off is one of the critical tasks that determine the cost of a construction project, and its result should be accurate and reliable. BIM-based quantity take-off is a very attractive process for practitioners since the quantity take-off can be done automatically in a fast and accurate way. However, the result of BIM-based quantity take-off can be varied depending on how BIM was modeled. As a project progresses, more detailed design information is getting available, and it can be expected that the degree of completeness and accuracy for the BIMbased quantity take-off is going to be improved as well. However, when estimation is performed at each stage of a project life-cycle, there is no way to measure or forecast how accurate of the quantity take-off result from the BIM data given at the current stage. Therefore, this research derived factors that affect the BIM-based quantity takeoff and developed a methodology and framework to measure and forecast the completeness of BIM-based quantity take-off. The measurement framework and index that are proposed by this research was verified and validated for their consistency and feasibility through six pilot projects.