BUE ACE1 Sustainable Vital Technologies in Engineering & Informatics 8-10 Nov 2016 Framework for HBIM Applications in Egyptian Heritage Mohamed Marzouk a, *, Mahmoud Metawie b, and Mohamed Ali b a Professor of Construction Engineering and Management, Structural Engineering Department, Faculty of Engineering, Cairo University,, Cairo, Egypt b Assistant Lecturer, Structural Engineering Department, Faculty of Engineering, Cairo University, Cairo, Egypt Abstract Building Information Modelling (BIM) radically changed the design and documentation processes in AEC industries. BIM coupled with 3D laser scanning (LIDAR) technologies revolutionized the built environment documentation methods. Many efforts were directed toward utilizing these technologies in the documentation and restoration of heritage buildings, adopting Heritage Building Information Modelling (HBIM). This paper presents a framework for HBIM application in Egyptian Heritage. The framework considers 3D laser scanning to document heritage buildings. A new approach of utilizing processed and segmented point clouds as a standalone is proposed for heritage information to be utilized as a platform which suffice a range of stakeholders needs. The proposed approach is capable to utilize processed point clouds to create different purpose BIM models with different level of development to suite different heritage documentation needs. A case study is presented to illustrate the practical aspects of proposed framework. Keywords: Egyptian Heritage; electronic documentation; laser scanning; HBIM. 1. Introduction Egypt is one of the richest countries in terms of heritage and monuments. However, there is no guarantee that the Egyptian heritage sites are not subjected to the risk of deep defects. During the recent years, Egypt has passed several waves of social and political unrest, and so does the whole Middle East region. During this period many historical sites were destroyed, or deeply defected, because of uncontrolled human activities in addition to typical wearing conditions coupled with insufficient restoration and maintenance. Uncontrolled human activities can range from unplanned urban development, failed restoration to social unrest and revolutions, to neglect and theft. Heritage documentation is the basic step of any restoration project. Many entities in Egypt are interested in the documentation of the heritage sites especially those registered as monuments in the ministry of state of antiquities. Geometric documentation of heritage sites or monuments is considered the most adequate documentation method. According to UNESCO, this method can be defined as follows the act of acquiring, processing, presenting and recording the necessary data for the determination of the position and the actual existing form, shape and size of a monument in the 3D space at a particular given moment in time (Amans et al., 2013). In Egypt, the traditional method of geometric documentation depends on digital photographs in addition to 2D projections with different scales, which ae produced by surveying techniques coupled with photogrammetry. These methods are well known for the stakeholders of heritage documentation, and formally recognized to be sufficient in most cases. However, these methods are time and labor consuming and fail to
2 Marzouk M., Ali M. / BUE ACE1 SVT2016 capture the exact fine details of most antiquities, and depends mainly on typical repetition of patterns, which miss the tiny imperfections which uniquely identify the art works. Accordingly, it is safe to assume that with the current approaches the rate of documentation of heritage is lagging behind the rate of loss or deterioration of invaluable antiquities. Accordingly, a new methodology needs to be adapted. This paper proposes framework for the geometric documentation of heritage sites (especially buildings), which pivots on utilizing the technology of 3D laser scanning (Light Detection and Ranging, i.e. LiDAR), and Heritage Building Information Modelling (HBIM). LiDAR technology depends on high speed 3D laser scanners, which send laser beams to the scanned objects in great intensity (high dense mesh, which can exceed a 0.6 mm x0.6 mm spacing). The device then calculates the coordinates of each point hit by the laser beam, thus creating a high density point cloud of the scanned object. Laser scanning has been used in different applications such as; reconstruction of 3D models of as-built industrial instrumentation (Son et. al. 2015), creation of semantically rich 3D building models (Xiong et. al. 2013), Generation of virtual models of cultural heritage (Andrés et. al. 2012), and conservation and research of African cultural heritage sites (Ruther et. al. 2009). BIM is simply a 3D representation of the built environment, in which the 3D modeled parametric objects are semantically linked to each other and to database that contains all their attributes, thus forming a single repository for the built environment information. BIM can be defined as the creation and use of the coordinated, consistent, computable information about a building project in design parametric information used for design decision making, production of high quality construction documents, prediction of the building performance, cost estimating, and construction planning (Krygiel and Nies 2008). BIM models were utilized in several purposes including design, engineering, visualization, conflict resolution, construction simulation, subcontractor coordination, and cost projection (Sattenini et al. 2011). HBIM is the heritage layer/add-in/library that is attached on top of traditional BIM applications. It poses all the power and benefits of BIM along with historical/heritage information. Generating heritage buildings/structures in a 3D HBIM environment are of substantial benefits, such as: remote visualization of the interior and exterior of structures; better understanding of the geometry of the structure; a repository of geometric and historical information; better evaluation of renovation strategies (Logothetis et al., 2015); 3D visualization on mobile, and virtual reality platforms. LiDAR technology coupled with HBIM proved valuable in the field of archeological exploration and heritage documentation of both small scale and large scale projects. With the aid of the cloud and virtual reality technologies, the appeal to utilize 3D technology is increasing for better dissemination and increased social awareness of the importance of heritage sites. 2. Proposed framework As indicated in previous sections, LiDAR and HBIM technologies are of great potential in the field of documenting heritage sites. This research proposes a framework for the geometrical documentation of heritage sites in Egypt as shown in Figure 1. The framework overcomes the weaknesses in the traditional geometrical documentation methods, which rely heavily on data acquisition techniques that require time and efforts such as survey points; direct measurements; and high quality digital imagery; photogrammetry; 2D Projections. LiDAR data and HBIM are the pivots of the proposed framework in order to overcome the weaknesses of the traditional methods. It is composed of four tiers; 1) Raw LiDAR data; 2) Processed point cloud; and 3) HBIM model. The output and benefits of every tier is inherited to the following because every tier is dependent on the product of the previous tier.
Marzouk M., Ali M. / BUE ACE1 SVT2016 3 Raw LiDAR Data Processed Point Cloud HBIM Model Figure 1: Proposed geometrical documentation framework 3. Case study This case study considers the scanning of Cairo University clock with a team that represents Construction Engineering Technology Lab (CETL) Faculty of Engineering, Cairo University (see Figure 2). Figure 2: CETL Team Scans Cairo University Clock
4 Marzouk M., Ali M. / BUE ACE1 SVT2016 The process of applying the proposed framework is divided into three phases; Phase 1: planning; Phase 2: 3D laser scanning of the site; Phase 3: processing of the High Density Point Cloud (HDPC). Phase1 is initiated by acquiring the layout of the site with all information collected via a total station survey and manual distance measurements. The team utilized a Z+F 3D laser scanner to acquire the HDPC. The planning depends on the number of scans required to capture the features of the Cairo University clock from all directions, while maintaining an adequate level of accuracy (HDPC density). The scanner has various density options each corresponds to a time of scan as displayed by Table 1. Accordingly, the high quality scan was selected with a corresponding 11 required scans to be performed in phase 2 (see Figure 3). Quality of scans Figure 3: Layout of the 11 Scans Table 1. 3D laser scanner scan quality vs. duration Mesh density Scan duration Scan size (cm/10 m) (approximately) Low 2.5 50 sec. 21 MB 5 Medium 1.25 1 m 40 sec. 50 MB 10 High 0.6 3 m 20 sec. 340 MB 15 Super high 0.3 6 m 40 sec. 1.3 GB 20 *the data processing is performed by a Dell OptiPlex 7020 work station Time to be exported to mesh processing software (min.) * Phase 3 was performed utilizing a Dell OptiPlex 7020 workstation for the processing purposes. Phase 3 started with the registration of the individual HDPC generated from multiple scans. Z+F software is used to register the scans. The registration process is achieved through identifying the same targets in different scans. The registered raw HDPC was produced as shown in Figure 4. Subsequently, the model is created using Geomagic and Autodesk Revit environments as shown in 5 and 6, respectively. Subsequently, the model is printed in 3D as a rapid prototyping for the generated model (see Figure 7).
Marzouk M., Ali M. / BUE ACE1 SVT2016 5 Figure 4: Point Cloud of Cairo University Clock Figure 5: Modeling Cairo University Clock using Geomagic
6 Marzouk M., Ali M. / BUE ACE1 SVT2016 Figure 6: Modeling Cairo University Clock using Autodesk Revit Figure 7: 3D Printing of Cairo University Clock Model
Marzouk M., Ali M. / BUE ACE1 SVT2016 7 4. Summary This paper started with indicating the value of LiDAR and HBIM technologies in the field of archeology and heritage documentation. The two technologies generate accurate geometrical models with high degree of resemblance to the actual modelled entity. HBIM adds a historical/heritage layer to BIM, so that when a 3D modeled heritage object is manipulated in the BIM environment, the historical/heritage information can be accessed semantically. Accordingly, framework for geometric documentation of heritage sites in Egypt pillaring on LiDAR and HBIM was proposed. The proposed framework is composed of four tiers of documentation, each with its own merits. Moreover, the proposed framework can handle any technical documentation workflow/process within its boundaries (hence, it is software independent), and is simple enough for practitioners and non-practitioners to grasp its main components. A case study was presented which displayed the documentation and visualization dissemination abilities of the framework, along with highlighting the simplicity of the flexible workflow, while indicating the need for deep technical knowledge and computational power during the implementation of the framework. References Amans, O.C., Beiping, W., Yao, Y.Z., Daniel, A.O., 2013. The need for 3d laser scanning documentation for select Nigeria cultural heritage sites. European Scientific Journal, Vol. 9, No. 24, 75-91. Andrés, A.N., Pozuelo, F.B., Marimón, J.R., and Gisbert, A.M. (2012). Generation of virtual models of cultural heritage. Journal of Cultural Heritage, Vol. 13, 103 106. Krygiel, E., and Nies, B. (2008). Green BIM: Successful Sustainable Design with Building Information Modeling. Wiley Publishing, Inc., Indianapolis, Indiana, US. Logothetis, S., Delinasiou, A., and Stylianidis, E., 2015. Building Information Modelling For Cultural Heritage: A Review. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. II-5/W3, 2015 25th International CIPA Symposium 2015, Taipei, Taiwan. Sattenini, A., Azhar, S. and Thuston, J. (2011). "Preparing a building Information Model for Facility Maintenance and Management." Proceedings of the 28 th International Symposium on Automation and Robotics in Construction, Seoul, South Korea. Son, H., Kim, C., and Kim, C. (2015). 3D reconstruction of as-built industrial instrumentation models from laser-scan data and a 3D CAD database based on prior knowledge. Automation in Construction, Vol. 49, Part B, 193 200. Xiong, X., Adan, A., Akinci, B., and Huber D. (2013). Automatic creation of semantically rich 3D building models from laser scanner data, Automation in Construction, Vol. 31, 325 337.