• Advances in Computational Design
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• 제5권2호
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• pp.127-146
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• 2020

Building Information Modeling (BIM) is increasingly used throughout the facility's life cycle for various applications, such as design, construction, facility management, and maintenance. For existing buildings, the geometry of as-built BIM is often constructed using dense, three dimensional (3D) point clouds data obtained with laser scanners. Traditionally, as-built BIM systems do not contain the material and textural information of the buildings' elements. This paper presents a semi-automatic method for generation of material and texture rich as-built BIM. The method captures and integrates material and textural information of building elements into as-built BIM using thermal infrared sensing (TIS). The proposed method uses TIS to capture thermal images of the interior walls of an existing building. These images are then processed to extract the interior walls using a segmentation algorithm. The digital numbers in the resulted images are then transformed into radiance values that represent the emitted thermal infrared radiation. Machine learning techniques are then applied to build a correlation between the radiance values and the material type in each image. The radiance values were used to extract textural information from the images. The extracted textural and material information are then robustly integrated into the as-built BIM providing the data needed for the assessment of building conditions in general including energy efficiency, among others.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.129-137
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• 2016

국내외에서 건축시설 중심의 BIM 라이브러리를 개발하여 보급하고 있으나, 개별 라이브러리 형상에 대한 물리적, 논리적 품질검토 방법을 정의하고 있지 않아 2D로부터 변환된 3D 라이브러리 모델의 신뢰성을 확보하는데 어려움이 있다. BIM 라이브러리는 자재 및 부재 제작업체들이 참여하여 컨텐츠를 구성하므로 개별 라이브러리의 제작 후 납품시 별도의 품질검토를 통해 인증을 받는 절차가 무엇보다 중요하다. 또한 그 활용에 범용성을 가져야 하므로 일관된 검토기준에 따라 객체의 품질을 확보하는 것이 필요하다. 따라서 본 연구에서는 국토교통부 표준도를 기반으로 작성된 토목분야 BIM 라이브러리를 토대로 기존 2D와 비교하여 물리적 및 데이터 관점에서 정확한 라이브러리 객체가 작성되었는지를 확인하기 위한 품질 검토 방법을 구성한다. 본 연구는 건축 및 토목분야의 자재 및 부재 제작업체들이 BIM 라이브러리 객체 납품 시 품질 검토 방법으로 널리 활용될 수 있을 것이다. 또한 As-Built BIM 모델의 품질검토를 위한 룰-셋(Rule-Sets) 정보로 활용되어 파라미터 기반의 자동화된 품질검증 시스템 구축에 활용될 수 있을 것이다.

• Architectural research
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• 제21권4호
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• pp.111-116
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• 2019

The premise of this research is the recent advancement of Building Information Modeling(BIM) Technology and Laser Scanning Technology(3D Scanning). The purpose of the paper is to amplify the potential offered by the combination of BIM and Point Cloud Data (PCD) for structural analysis. Today, enormous amounts of construction site data can be potentially categorized and quantified through BIM software. One of the extraordinary strengths of BIM software comes from its collaborative feature, which can combine different sources of data and knowledge. There are vastly different ways to obtain multiple construction site data, and 3D scanning is one of the effective ways to collect close-to-reality construction site data. The objective of this paper is to emphasize the prospects of pre-scanning and post-scanning automation algorithms. The research aims to stimulate the recent development of 3D scanning and BIM technology to develop Scan-to-BIM. The paper will review the current issues of Scan-to-BIM tasks to achieve As-Built BIM and suggest how it can be improved. This paper will propose a method of coordinating and utilizing PCD for construction and structural analysis during construction.

• 한국건설관리학회논문집
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• 제17권3호
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• pp.32-42
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• 2016

현재 국내 대부분의 토목 건축 구조물이 BIM 정보가 부재한 상황에서 준공 BIM(as-built BIM)의 수요가 점차 증가하고 있다. 준공 BIM 구축을 위한 공간자료 취득에는 고밀도의 포인트 클라우드를 생성할 수 있는 레이저 스캐너가 주로 활용되고 있다. 하지만 기존의 고정식 스캔 시스템은 이동이 번거롭고, 정밀한 위치 선정이 필요 하며, 스캔 자료 정합을 위해 별도의 표지를 설치하거나 공액점을 추출하는 과정이 필요하다. 본 연구에서는 수작업을 최소화하기 위해 기존의 고정식 스캔 시스템을 대체할 수 있는 이동식 스캔 시스템을 제안하고자 하며, 기반 기술로 graph-based SLAM을 적용하였다. 테스트 장비는 총 세 개의 2차원 스캐너를 탑재하고 있으며, 중앙의 한 개는 수평으로 설치되어 graph 구축을 통한 이동경로취득에 사용되었고, 좌우 두 개는 수직으로 설치되어 시스템 진행의 연직 방향으로 주변 구조물에 대한 3차원 스캔 정보 취득에 사용되었다. 개발된 graph-based SLAM은 이동경로 상에 누적된 위치오차를 해소하기 위한 loop closure 처리 방법으로 Adaboost 기계학습을 적용하였다. 이는 특히 본 연구에서 사용한 장비와 같이 기계학습을 위한 다수의 feature 정보를 제공할 수 있는 멀티 스캐너 시스템에 적합한 방식이며, 두 실내공간을 대상으로 한 테스트에서 단일 스캐너 대비 false positive rate를 각각 7.9% 및 13.6%까지 줄일 수 있었다. 최종적으로 연구대상지역의 2차원 및 3차원 지도 구축을 통해 개발된 graph-based SLAM의 효용성을 확인하였다.

• 설비공학논문집
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• 제25권4호
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• pp.216-224
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• 2013

Facility data is created throughout the design and construction phase. But the most facility managers bear significant costs that arise from the lack of interoperability with facility lifecycle. This paper is concerned with the way to collect facility data using BIM technology. The aim of this paper is to suggest BIM data modeling guide for the facility management using the information that need to be delivered from design and construction phase to operation and management phase. The BIM data modeling guide focus on the properties of mechanical equipment. It is to be hoped that this study will contribute to collect facility data from as-built BIM data and to build facility management system database without difficulty.

• 한국BIM학회 논문집
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• 제9권2호
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• pp.11-20
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• 2019

The use of drones and laser scanners have the potential to drastically reduce the time and costs of conventional techniques employed for field survey of cultural heritage buildings. Moreover, point cloud data can be utilized to create an as-built Building Information Model (BIM), providing a repository for consistent operations information. However, BIM creation is not a requisite for heritage buildings, and their technological possibilities and barriers have not been documented. This research explored the processes required to convert a heritage university building to a BIM model, using existing off-the-shelf software applications. Point cloud data was gathered from drones for the exterior, while a laser scanner was employed for the interior of the building. The point clouds were preprocessed and used as references for the geometry of the building elements, including walls, slabs, windows, doors, and staircases. The BIM model was subsequently created for the individual elements using existing and custom libraries. The model was used to extract 2D CAD drawings that met the requirements of Korea's heritage preservation specifications. The experiment showed that technical improvements were needed to overcome issues of occlusion, modeling errors due to modeler's subjective judgements and point cloud data cleaning and filtering techniques.

• 한국BIM학회 논문집
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• 제7권4호
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• pp.8-20
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• 2017

When it comes to set up the BIM through the reverse engineering, the level of detail(LoD) required for finalized outcomes is different from each purpose. Therefore, it is necessary to establish some concrete criteria which describe the definition of LoDs on 3D modeling for the purpose of each reverse engineering. This research shows the criteria of the 1) positional accuracy, 2) generalization level, 3) scale level, 4) scope of description, and 5) the area available for application by classifying LoD from 1 to 6 on 3D modeling for each purpose of reverse engineering. Moreover, through applying those criteria for the 3D point cloud dataset of building made by terrestrial LiDAR, this research finds out the working hour of 3D modeling of reverse engineering by each LoDs according to defined LoD criteria for each level. It is expected that those findings, how those criteria of LoD on reverse engineering are utilized for modeling-workers to decide whether the outcomes can be suitable for their budget, applicable fields or not, would contribute to help them as a basic information.

• 한국콘텐츠학회논문지
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• 제22권5호
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• pp.276-287
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• 2022

1990년대 이후로 문화유산 분야에서도 디지털 기술의 적용이 활발히 진행되고 있으며, 이는 기존에 기록, 보관되고 있던 문화원형 데이터를 활용하는 방안으로 문화유산의 새로운 활용 가능성을 제시하였다. 특히, COVID-19, 시간적 제약과 같은 다양한 외부 상황으로 문화유산을 향유하는 방법이 다변화되었고, 건물 자체를 옮길 수 없는 건축문화유산에서 비대면 디지털 콘텐츠의 활용은 중요한 역할을 하게 되었다. 건축문화유산의 진정성을 올바르게 표현하는 방안으로 건축정보모델(BIM) 기술이 고려되지만, 단순히 BIM으로 건축문화유산 콘텐츠를 만드는 것으로는 문화유산의 진정성을 표현한다고 할 수 없다. 따라서 콘텐츠 제작 과정의 신뢰성을 인증된 기관을 통해 보여주며, 콘텐츠 상에서 부재의 정보 제공이 필요하다. 본 연구는 건축문화유산 콘텐츠 제작에서 신뢰성 확보와 진정성 표현을 위한 방안을 제시하여, 디지털 문화유산 분야에 기여하고자 한다.

• 한국BIM학회 논문집
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• 제9권4호
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• pp.62-74
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• 2019

Because the existing BIM platform is based on user services, the focus is on the development of SaaS (Software as a Service), which provides business services online. However, since a harbor is a security facility, the harbor BIM platform is preferably provided in a private form, rather than relying on the infrastructure environment provided by external cloud providers. Therefore, this study analyzes and reviews the main functions to be provided as SaaS services of the harbor BIM platform. The goal is to build a cloud-based harbor BIM platform that can provide this service to users. To this end, we built IaaS (Infrastructure as a Service) environment of the harbor BIM platform based on the open source Open Stack and integrate and develop PaaS environment with Open Shift applied with IaaS. We applied the GPU to the harbor BIM platform to verify the performance of the harbor BIM platform, and found that the rendering and loading times are improved. In particular, it is expected to reduce the cost of introduction and provide it as the basic cloud environment of similar BIM platform for infrastructure facilities.

• 한국측량학회지
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• 제33권6호
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• pp.557-567
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• 2015

With the increasing demands of 3D spatial information in urban environment, the importance of point clouds generation techniques have been increased. In particular, for as-built BIM, the point clouds with the high accuracy and density is required to describe the detail information of building components. Since the terrestrial LiDAR has high performance in terms of accuracy and point density, it has been widely used for as-built 3D modelling. However, the high cost of devices is obstacle for general uses, and the image-based 3D reconstruction technique is being a new attraction as an alternative solution. This paper compares the image-based 3D reconstruction technique and the terrestrial LiDAR in point of establishing the as-built BIM of outdoor structures. The point clouds generated from the image-based 3D reconstruction technique could roughly present the 3D shape of a building, but could not precisely express detail information, such as windows, doors and a roof of building. There were 13.2~28.9 cm of RMSE between the terrestrial LiDAR scanning data and the point clouds, which generated from smartphone and DSLR camera images. In conclusion, the results demonstrate that the image-based 3D reconstruction can be used in drawing building footprint and wireframe, and the terrestrial LiDAR is suitable for detail 3D outdoor modeling.