• International conference on construction engineering and project management
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• 2013.01a
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• pp.419-425
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• 2013

Recently AEC industry has required construction automation according to becoming large and complex. Thus BIM-based construction project is increased and used in whole fields of AEC industry. Quantity take-off and estimation fields are important factor for decision-making in conceptual and schematic design stages of construction projects. The purpose of this study improves reliability of the estimation through QTO based on Open BIM. Scope and method to apply QTO is to select conceptual design stage through LoD(Level of Detail) in AEC field and to extract information from BIM model through analysis of IFC structure. This study proceeds three step to make BIM model and check the model quality and calculate QTO. The methodology of QTO using IFC is to verify of result in this study and expects utilizing in design stage of construction projects. The result from this study is expected to decrease the risk factor and time of estimation in the project early phase through improving reliability of schematic estimation.

• Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.16-25
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• 2015

Since construction projects are large and complex, it is especially important to provide concurrent construction process to BIM models with construction automation. In particular, the schematic Quantity Take-Off (QTO) estimation on the BIM models is a strategy, which can be used to assist decision making in just minutes, because 70-80% of construction costs are determined by designers' decisions in the early design stage. This paper suggests a QTO process and a QTO prototype system within the building frame of Open BIM to improve the low reliability of estimation in the early design stage. The research consists of the following four steps: (1) analyzing Level of Detail (LOD) at the early design stage to apply to the QTO process and system, (2) BIM modeling for Open BIM based QTO, (3) checking the quality of the BIM model based on the checklist for applying to QTO and improving constructability, and (4) developing and verifying a QTO prototype system. The proposed QTO system is useful for improving the reliability of schematic estimation through decreasing risk factors and shortening time required.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.5
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• pp.145-152
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• 2019

In this study, rebar QTO(Quantity Take-Off) was quickly produced from the BIM model prepared by Revit in the early design phase, and the available premium rates were quantitatively presented. For this purpose, the amount of rebar calculated using the BuilderHub, which specializes in calculating rebar QTO, was analyzed according to various factors such as member type, rebar diameter, building size, item type, and order length, and the effect of each factor on the rebar QTO was determined. In addition, the BIM model generated on Revit was used to establish parameters and processes required to produce rebar QTO, and proposed a rebar premium rate and a stirrup/hoop premium rate based on the BuilderHub output results. Through this study, it is expected that a rapid and efficient comparative evaluation of rebar QTO will be possible according to various structural design alternatives in the early design phase.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.4
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• pp.197-205
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• 2022

In this paper, a retaining wall system, developed using building Information modeling (BIM), is presented. Based on the information from a literature review, elementary technologies for the system were defined and developed. First, for the elementary technology, BIM libraries were constructed using standards and previous study results to achieve versatility and reusability. Second, methods for determining the quantity take-off (QTO) of a retaining wall were reviewed for an earth-work calculating system. Additionally, inverse distance weighting interpolation was used to generate topography. Finally, four formulas for calculating the QTO were proposed and devised for each element. After its development, the BIM system was analyzed and verified through comparison with a two-dimensional drawing-based QTO. The proposed system is deemed to be practical for determining the QTO of retaining walls and earth works. The contributions and limitations of the research are discussed in this paper.

• 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.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.289-293
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• 2015

The construction industry has been evolving with the development of information technology. According to this trend, the current industry changes from 2d drawings to Building Information Modeling(BIM). Current studies on the BIM-based estimation have problems such as Quantity Take-Off(QTO) specificity toward a particular software, the uncertainty of the amount in accordance with the model quality. These studies focus on QTO based on BIM rather than schematic estimation. In addition, studies on the connection with the QTO and unit cost for schematic estimation are insufficient. The purpose of this study is to propose schematic estimation process by utilizing construction codes and QTO in architectural object BIM libraries. Construction codes are classified in detail in order to input codes inside each. This study has connected unit cost and construction classification codes that obtain from BIM model. The results of this study will be helpful in decision-making and communication for schematic estimation of the design phase. It will improve the efficiency and reliability problems of existing schematic estimation.

• Journal of the Korea Institute of Building Construction
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• v.24 no.4
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• pp.447-458
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• 2024

This study investigates the effectiveness of Building Information Modeling(BIM) software, specifically SketchUp and Revit, in reducing errors during quantity take-off(QTO) for complex building elements. While 3D modeling offers advantages, existing software may not fully account for manufacturing discrepancies, such as variations in concrete cover thickness and reinforcing bar radius. To address this limitation, this research proposes a BIM-based QTO method for high-insulation wall panels with intricate details. The method utilizes a BIM family library, focusing on key parameters like concrete cover thickness and inner radius of shear reinforcement. A case study compared the cross-sectional details of a wall panel modeled in Revit with the actual manufactured specimen. The analysis revealed a 12% reduction in modeled concrete cover thickness and a 1.27 times larger modeled inner radius of the shear bar compared to the real-world values. The proposed method incorporates these manufacturing variations into the Revit model of the high-insulation wall panel. Software like Navisworks facilitates the identification and correction of any material interferences arising from these adjustments. Furthermore, the method employs a unit wall concept(1m²) to account for the volume of various materials, including insulation and splice sleeves at joints. This allows for the identification of a similar existing family within the BIM library(e.g., "Double RC wall with embedded insulation") that reflects the actual material quantities used in the wall panel. By incorporating these manufacturing-induced variations, the proposed method offers a more accurate QTO process for complex high-insulation wall panels. The "Double RC wall with embedded insulation" family within the Revit program serves as a valuable tool for material quantity estimation in such scenarios.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6488-6494
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• 2013

Recently, BIM has attracted attention as a technology to improve the construction productivity. The BIM standards to be applied to the BIM project are necessary for using or connecting the current 2D-based drawing standards. To develop the standard for BIM-based QTO and cost, this paper focused on using QDBEx, which was applied to road project cost management and connecting QDBEx with IFC, which is the BIM data delivery format. The IFC schema was evaluated to determine if it is possible to use the converts to the QDBEx XML file. As a result, 66% of the whole was available to connect directly, and 17% was available to connect through the processing of instance. The remaining 17% was evaluated to determine if it was available to connect. In the future, improvements in the schema will be suggested based on these results.