Autodesk ReCap Research Articles

Porównanie komercyjnego i darmowego oprogramowania do przetwarzania chmur punktów

Terrestrial laser scanning technology is becoming increasingly common for automated spatial data acquisition and digitization in the fields of surveying, civil engineering and architecture. The data from measurements made with terrestrial laser scanners are a huge array of points in space, called a point cloud, which describes the captured surface of the object under study. The point cloud processing is performed in specialized software products for handling measurements from laser scanners, which provide different possibilities for manipulating the point cloud and forming different results. The software available on the market differs according to its data processing capabilities and functionalities, application areas, methods used, manufacturer and cost. To be able to perform spatial data processing and analysis correctly and with high quality, it is important to understand the available functionalities of the different software products and their advantages and disadvantages compared to others. A comparison is made for three software packages for point cloud processing - Autodesk ReCap Pro, CloudCompare and Trimble RealWorks. The different functionalities available in the products are described and presented on small building measurements along with their performance accuracy and efficiency. The strengths and weaknesses of the different software products are identified through the comparison performed. The first section describes the basic principles of the terrestrial laser scanning method. In section two, the different point cloud processing software products on the market are presented, together with a description of the different file formats for data exchange and a theoretical section on point cloud registration, filtering, and modelling. The third section contains a presentation of the main functions and processing capabilities in Autodesk ReCap Pro, CloudCompare and Trimble RealWorks software. The fourth section describes the data used for the study, the measurements performed, their processing and results in the three software, together with an assessment of accuracy by control measurements. Section five contains conclusions and implications.

Побудова твердотілої моделі історичного об’єкту: на прикладі форту «Марушка Ліс»

Purpose of this work is to use terrestrial laser scanning for analysis and construction of a digital model of the fort “Marushka Lis” focusing on the process of data collection, processing, and their further use, particularly for web mapping of post-military sites. In the modern world, the preservation and restoration of historical structures is an important task that requires the application of advanced technologies. Methodology. Terrestrial laser scanning serves as an indispensable tool in this process, providing accurate and detailed spatial data. A technological scheme for creating a digital model of a historical object has been proposed. The study of historical objects using various methods of information collection was considered, namely: topographic surveying, terrestrial digital photogrammetry, terrestrial laser scanning, ground-penetrating radar studies, tachymetric surveying, GNSS. The methodology for creating a digital model of a historical object and the presented technological scheme, which includes data collection, processing of the obtained results, and output data, are described. Results. A comprehensive approach was applied to create the model, which included studying the history of the object, terrestrial laser scanning, terrestrial digital photogrammetry, and conducting geodetic measurements. A key aspect was the accurate and detailed reproduction of all architectural and structural elements of the fort. The use of software such as Leica Cyclone REGISTER 360, Autodesk ReCap, and Autodesk Revit allowed the integration of collected data into one accurate and detailed model. The sequential execution of work according to the proposed methodology enabled the creation of a digital model of the fort “Marushka Lis.” Scientific novelty and practical significance. The scientific novelty lies in the use of terrestrial laser scanning and 3D modeling for the reconstruction of a destroyed post-military object. The obtained digital model of the fort “Marushka Lis” will be used in web mapping of post-military sites in Lviv region.

Indoor Space Modeling and Parametric Component Construction Based on 3D Laser Point Cloud Data

In order to enhance modeling efficiency and accuracy, we utilized 3D laser point cloud data for indoor space modeling. Point cloud data was obtained with a 3D laser scanner and optimized with Autodesk Recap and Revit software to extract geometric information about the indoor environment. Furthermore, we proposed a method for constructing indoor elements based on parametric components. The research outcomes of this paper will offer new methods and tools for indoor space modeling and design. The approach of indoor space modeling based on 3D laser point cloud data and parametric component construction can enhance modeling efficiency and accuracy, providing architects, interior designers, and decorators with a better working platform and design reference.

A Pedagogical Approach Using Digitalization and Heritage Building Information Modelling (HBIM) for a New Practice in Architecture and Archaeology

In the past years, architectural heritage was represented and described through 2D plans, sections, perspective drawings, pictures, and texts. But, in the last decades, with the development of digital tools such as 3D scanner laser and photogrammetry, new technologies have been introduced in the digital survey of architectural heritage and 3D modelling. In this regard, we noticed that students, architects, and archaeologists still do not use photogrammetry and lasergrammetry in their work. Some of them found those methods difficult and expensive. This paper aims to describe a methodology of digitizing architectural artefacts based on digital tools such as photogrammetry and lasergrammetry that allows representing realistic and accurate 3D models and then to explain the steps that lead to introducing photogrammetric model from Autodesk recap photo software in the Autodesk Revit software to have a Heritage Building Information Modeling (HBIM) project that is useful for architectural intervention on cultural heritage using digital platform allowing multidisciplinary collaboration in architectural projects. The field of experimentation is our teaching courses with the students at the national school of architecture and urban planning in Tunisia in different sites. The student’s results are promising in the new practice of Digital Architecture and Digital Archeology and the HBIM can be a conception aid design.

APPLYING HERITAGE BUILDING INFORMATION MODELLING (HBIM) TO LOST HERITAGE IN CONFLICT ZONES: AL-HADBA’ MINARET IN MOSUL, IRAQ

Abstract. Arguably, the weaponry development during the last century aided in destroying cultural heritage now like never before, this is illustrated in the recent destruction of irreplaceable heritage sites in Syria and Iraq due to conflict. Heritage is often destroyed to demoralise local societies, erase memory, cause extensive economic loss and assert supremacy. Therefore, post-conflict recovery needs to aid in re-establishing damaged heritage as a beacon for cultural and social recovery. Using Heritage Building Information Modelling (HBIM) could provide tools to digitally recover damaged structures. Yet, there is little research on the implementation of HBIM in conflict zones. Thus, this study seeks to apply HBIM workflows to damaged heritage by virtually reconstructing Al-Hadba’s minaret, one of Iraq’s iconic landmarks, destroyed in 2017 by the “Islamic state”. The photogrammetry process used freely available web-based images that were imported into three photogrammetry software: Agisoft Metashape©, Autodesk Recap©, and AliceVision Meshroom to compare crowdsource processing capabilities. The resulting point cloud was scaled using onsite measurements of the minaret’s remaining base and imported into Autodesk Revit© to produce a HBIM model. While the process produced comprehensive digital documentation of Al-Hadba’, it revealed many challenges confronting digital reconstruction in conflict zones such as lacking documentation, conflict of historical information, crowdsource data constraints, and their effects on the resulting point cloud’s quality. The study highlights potential tools to support post-conflict recovery and attempts to present an accessible approach that could be used as a baseline in conflict zones with limited resources to aid in the cultural recovery of valuable heritage sites that represent an irreplaceable part of their community’s collective memory.

Performance comparison analysis of 3D reconstruction modeling software in construction site visualization and mapping

Unmanned aerial vehicle (UAV) technology has overcome the limitations of conventional construction management methods using advanced and automated visualization and 3D reconstruction modeling techniques. Although the mapping techniques and reconstruction modeling software can generate real-time and high-resolution descriptive textural, physical, and spatial data, they may fail to develop an accurate and complete 3D model of the construction site. To generate a quality 3D reconstruction model, the construction manager must optimize the trade-offs among three major software-selection factors: functionalities, technical capabilities, and the system hardware specifications. These factors directly affect the robust 3D reconstruction model of the construction site and objects. Accordingly, the purpose of this research was to apply nine well-established 3D reconstruction modeling software tools (DroneDeploy, COLMAP, 3DF+Zephyr, Autodesk Recap, LiMapper, PhotoModeler, 3D Survey, AgiSoft Photoscan, and Pix4D Mapper) and compare their performances and reliabilities in generating complete 3D models. The research was conducted in an eco-home building at the University of Technology, Malaysia. A series of regression analyses were conducted to compare the performances of the selected 3D reconstruction modeling software in alignment and registration, distance computing, geometric measurement, and plugin execution. Regression analysis determined that among the software programs, LiMapper had the strongest positive linear correlation with the ground truth model. Furthermore, the correlation analysis showed a statistically significant p-value for all software, except for 3D Survey. In addition, the research found that Autodesk Recap generated the most-robust and highest-quality dense point clouds. DroneDeploy can create an accurate point cloud and triangulation without using many points as required by COLMAP and LiMapper. It was concluded that most of the software is robustly, positively, and linearly correlated with the corresponding ground truth model. In the future, other factors involving software selection should be studied, such as vendor-related, user-related, and automation factors.

The Use of Smartphone Photogrammetry to Digitise Transtibial Sockets: Optimisation of Method and Quantitative Evaluation of Suitability.

The fit of a lower limb prosthetic socket is critical for user comfort and the quality of life of lower limb amputees. Sockets are conventionally produced using hand-crafted patient-based casting techniques. Modern digital techniques offer a host of advantages to the process and ultimately lead to improving the lives of amputees. However, commercially available scanning equipment required is often expensive and proprietary. Smartphone photogrammetry could offer a low cost alternative, but there is no widely accepted imaging technique for prosthetic socket digitisation. Therefore, this paper aims to determine an optimal imaging technique for whole socket photogrammetry and evaluate the resultant scan measurement accuracy. A 3D printed transtibial socket was produced to create digital and physical twins, as reference models. The printed socket was photographed from 360 positions and simplified genetic algorithms were used to design a series of experiments, whereby a collection of photos were processed using Autodesk ReCap. The most fit technique was used to assess accuracy. The accuracy of the socket wall volume, surface area and height were 61.63%, 99.61% and 99.90%, respectively, when compared to the digital reference model. The scanned model had a wall thickness ranging from 2.075 mm at the top to 7.758 mm towards the base of the socket, compared to a consistent thickness of 2.025 mm in the control model. The technique selected did not show sufficient accuracy for clinical application due to the degradation of accuracy nearer to the base of the socket interior. However, using an internal wall thickness estimation, scans may be of sufficient accuracy for clinical use; assuming a uniform wall thickness.

UAV-BASED PHOTOGRAMMETRY DATA TRANSFORMATION AS A BUILDING INSPECTION TOOL: APPLICABILITY IN MID-HIGH-RISE BUILDING

The photogrammetric concept is used as a practical implementation of this study. Data management is proposed as an active contribution in the process of data integration and data in-operability to develop solutions based on UAV-based Photogrammetry as part of building inspection activities. Point Cloud adjusts the main role as data to initialize objects whose information can be represented in 2D / 3D / 4D rich-data format. Decision making on each management framework is planned with the DJI Go and Pix4D Capture Application which is controlled by a smartphone that has been pre-configured for the plan UAV flights. The flight plan quality control, flight mission supervision, and data acquisition results are important factors in the management and related infor-mation framework. The Point Cloud created by the SfM (Structure from Motion) application is then imported by Autodesk Recap and reconstructed in Revit BIM. The 3D Point Cloud is lastly enhanced with some practically detailed information to contribute to the data management experiment. The collaboration model of this study is presented using AR / VR (Augmented Reality / Virtual Reality) to enable mobile monitoring as a research objective and substantial examination. The essence of this study is to develop UAV-based Photogrammetry / BIM / AR-VR as a method to reduce the risk of data mismatches, monitor communications, and increase the impact of practical instructions on de-cision making on building inspection activities. The results of each verified workflow show that the methodology applied produces informational and visual data products that allow user mobility within the scope of building inspection and monitoring. Furthermore, device limitations do not affect the data acquisition process to provide user safety and efficiency.

Accuracy Assessment On Point Cloud Dataset from Terrestrial Laser Scanner with Different Objects Surface Properties

Terrestrial laser scanner is the instrument used for generating and receiving point cloud data from the ground either using tripod or handheld. This study focused on identifying the effect of different object surface properties in most standard building materials used towards the accuracy of point cloud captured using TLS that is important for guiding the observer before making measurement. Practically, all the captured data for each surface used the similar aspects in terms of resolution, quality, and point cloud distance using a single scan method. Next, all data processing were processed and computed using FARO Scene, ArcScene and AutoDesk Recap software that are capable to analyse through the reconstructed 3D model. It had been found that cement wall reacts better with the point clouds even the wood expected to give a good result as a few factors had given big impacts towards each of the object surfaces. The finding from this study had identified the reaction of the point clouds on each different object surfaces with various properties varies depending on the roughness, reflectivity strength, colors, textures and type of surfaces that became major indicator to determine accuracy of the distributions and arrangements of point clouds on each surface.

Creating a digital relief model by aerial photography materials in Civil 3D software

Research of certain aspects of using a digital elevation model (DEM), their classification and methods of obtaining in the Civil 3D software is presented in this article. A land plot with vegetation and the building of the educational building of the NULES of Ukraine was used as an object for the study. The analysis of aerial photography materials of the territory of the research object is carried out. A digital point cloud was created, which was taken as a basis for the further construction of digital elevation models. Сlassification of surfaces in the Civil 3D software is offered in article. An algorithm for the formation of plane components and data filling is considered. Highlighted the problems that arise in a robot with a cloud of points and surface formation using Autodesk ReCap and Civil 3D. The main advantages and disadvantages of building a relief on the basis of point clouds formed on the basis of aerial photography of the terrain are shown. Attention is focused on the main ways to reduce the identified shortcomings. The functionality and capabilities of Civil 3D and Autodesk ReCap software, as well as the features of constructing surfaces based on different initial data, are considered. The comparison of the DEM (generated using the Autodesk Civil 3D software) and the topographic plan (generated as a result of tacheometric survey) is given.

Фрактальные графики эффективности оптимизации топологии в решении проблемы зависимости прочности от сетки

In this research is solved the problem for determining of dependencies describing the strength redundancy of a part obtained by means of topology optimization using the SIMP method under a variety of grid’s finite elements. For this purpose, in the research was performed a digital experiment, during which almost fifty variants of part’s computer models were obtained, and their mechanical properties were studied. Based on the obtained data were constructed plots for the strength efficiency of topological optimization, which reflect fractal properties of part’s strength parameters changing.
 Upon reaching the research goal were solved the problems of software selection and applying a programs combination, which allowed automate the creation of models based on the topology optimization results. The main tool for topology optimization was the Autodesk Fusion 360 product, providing a free access to cloud computing, and Autodesk ReCap Photo was used when models converting.
 On the results of the experiment were formulated recommendations for obtaining the part’s optimized topology without critical defects of shape, using the SIMP method. With great probability, these recommendations are important when using other methods for topological optimization, such as ESO, BESO, or Level-Set.
 The received recommendations were tested in solution the problem of increasing the structures’ strength efficiency on the example of the rocker-Bogie wheel suspension using in modern Curiosity-type Mars rovers. The topology optimization results are openwork parts that can withstand heavy loads at low weight. This was confirmed by strength analysis, which had showed an increase in specific strength up to 13.5 times, relative to the prototype used in the Curiosity-type Mars rover’s suspension.

Design of Methodological Procedure of Hall Modeling in the Revit Software

In this article, we will show you how to use the Revit software application developed by Autodesk. This software application is focused on parametric 3D modeling and drawing of elements used in the construction industry. It is one of the BIM tools (Building Information Modeling), which is the only one that provides the project from the concept phase to construction and throughout the use and management of the building. We'll also show you the benefits of Autodesk ReCap software, which is used as a tool to clean up the point cloud after scanning, show you the results of working after editing the point cloud and transferring it to Revit software.

Robot-assisted 3D digital reconstruction of heritage artifacts: area similarity approach

PurposeThis paper aims to propose a system to acquire images automatically for digital reconstruction of heritage artifacts using a six-degree of freedom industrial manipulator.Design/methodology/approachA virtual environment is created using Robot Studio® software to integrate the trajectory and differential motion of the robot manipulator and the motion of camera while acquiring images. A new area similarity matrix method is proposed to reduce the number of images required for digital reconstruction using Autodesk Recap® software. Real-time experiments have been performed using objects such as minion, ultimaker robot and cube. Evaluation of the digital reconstruction is conducted using the contour area matching method.FindingsThe number of images required for reconstruction based on area similarity matrix method is reduced to 63 per cent when compared with the random selection method. Quality parameters such as surface area, volume, number of defect holes, vertices and faces are enhanced for the proposed method.Research limitations/implicationsDigital reconstruction of large-sized heritage artifacts cannot be performed in this setup. But this can be overcome by fixing the manipulator on a mobile platform or overhead crane. This paper does not discuss the reconstruction of partially damaged heritage artifacts, which could be accomplished based on deep learning techniques.Practical implicationsUsing this approach, off-the-shelf heritage artifacts and large-scale objects can be reconstructed digitally with a minimum number of images and without compromising the quality of original models.Originality/valueTo the best of the authors’ knowledge, area similarity-based approach in 3D digital reconstruction by coupling the kinematics of an industrial manipulator and camera is proposed for the first time. A fully automated digital reconstruction technology to preserve valuable heritage artifacts has been developed. It also highlights the space constraints of the industrial manipulator in digital reconstruction.

Photogrammetry is for everyone: Structure-from-motion software user experiences in archaeology

In this study, Structure-from-Motion (SfM) photogrammetric software was used to create 3D models of the Tyler house (Mound, TX) and Eyrie house (Holyoke, MA), both mid-19th century ruins. We compared the resulting models to evaluate the user experience for non-specialists between two different but popular software options for SfM modeling used by archaeologists. We addressed the differences in rendered models by acquisition method, UAV (unmanned aerial vehicle) or terrestrial photography and, compared models using metric and interpretive outputs. We used AgiSoft’s PhotoScan (v. 1.4, now Metashape) and Autodesk ReCap Photo (v. 2018) to generate models for this study. Using CloudCompare (v.2.9.1), we calculated cloud-cloud distances, average distances between points, and the standard deviation between model pairs. Clouds were accurate to within 0.03 cm with varying degrees of standard deviation. This result is likely due to differences in methodology, such as the degree of photo overlap between acquisition methods and software rendering parameters. These results may help the archaeological community in selecting software, increasing awareness of point cloud and user-induced variations, and refining acquisition methods when recording archaeological sites. This paper is targeted towards informing non-specialists about options when selecting SfM software.

The use of video camera to create metric 3D model of engineering objects

The article presents the possibilities of using a video camera to create a 3D metric model of engineering objects using Agisoft and CloudCompare software. Traditional photogrammetry technique does not always match up with production urgency needed by the market. Complexity is seen when used in huge objects leading to rise of cost, time and tediousness of the work. The use of Video Camera technique here termed as videogrammetry technique is comparable to taking pictures, however, it allows to speed up the process of obtaining data, which in many cases is a key element in anyb any project or research. The analysis of the quality of 3D modelling of the three filmed objects was performed, which allowed the authors to refine the procedure for acquiring images for spatial analyses. The applied technique of “videogrammetry” is comparable to taking pictures, but allows the data acquisition process to speed up, which in many cases is a key element in field research. 3D objects videos from no-metric camera were processed by Agisoft Metashape. To be able to assess the accuracy of the videogrammetry data, a well-established Laser scanner technique’s data was used for comparison. The laser scanner data were pre-processed in Autodesk Recap. Manual registration was performed utilizing 14 points from the three scans. The two 3D models were exported to CloudCompare software for comparison and further analysis. An analysis of the quality of 3D modelling of the three objects filmed was performed, which allowed refining the procedure for obtaining images for spatial analysis. The article presents the possibilities of using a non-metric mobile phone video camera “videogrammetry” to create a metric 3D model of engineering objects using Agisoft and CloudCompare software. In CloudCompare a registration, cloud to cloud (C2C) and profile to profile analysis was performed to determine the uncertainty of the 3D model produced from videogrammetry data determined as distance of separation between the two models. Results show average distance of separation between laser scanner and videogrammetry derived 3D model point cloud to be 34cm, the average profile separation was 25 cm in XY plane and 1.9 cm in Z-plane. Using Cloud to Cloud PCV the average difference of 84 cm was determined.

Ranking of Heritage Building Conversion Alternatives by Applying BIM and MCDM: A Case of Sapieha Palace in Vilnius

A balance (symmetry) between socio-cultural and socio-economic benefits as a part of the economic, social, and cultural development policy of each city and country should be assured when converting built heritage. To anticipate building conversion priorities and opportunities, modern technologies can be employed. However, currently the activity of reconstruction of heritage buildings is part of the construction domain wherein modern digital technologies have been the least ever applied. Therefore, photogrammetry and the 3D modeling of existing heritage buildings was suggested. A case study of Sapieha Palace, built in the Baroque style in 1689–1691 in Vilnius, Lithuania was explored in this research. The applied technologies and software (Agisoft Photoscan, Autodesk ReCap and Autodesk Revit) allowed for the creation of a high quality and accurate model involving both the textured exterior of the building and the interior layout. In addition, the valuable features of a building were identified and marked in a three-dimensional digital model. Based on the model, the authors formulated possible conversion alternatives of the building and identified the associated decision-making criteria, as well as determined their relative significance by an expert survey method. The authors suggested the application of the multiple criteria decision making (MCDM) method under uncertainty, namely the rough weighted aggregated sum product assessment (WASPAS), for ranking alternatives according to multiple criteria. Therefore, the suggested integration of modern digital technologies and decision-making models helps to assure the rational conversion decision of built cultural heritage based on high accuracy data as well as contributing to the sustainable development of engineering processes.

Digitalization of Ancient Sculpting Models and 3D Design Using Photogrammetry Methodology

The digitization of ancient sculptures is particularly relevant and necessary in relation to the preservation of the cultural heritage. And the studied ancient models have their unique identity in terms of their visual and functional qualities. In parallel, the study aims to optimize the technological process related to photogrammetric measurements and calculations, technological tools and specialized software applications such as Autodesk ReCap, Blender and MeshMixer. The used models in the article are for re-presentation of popular ancient models & artifacts from city of Varna (by the ancient name Odessos). By using a 3D print device, one of the resulting digitized models of an ancient angel will materialize by applying specific techniques to redesign its geometry. The completed 3D printed item of re-designed model of ancient stone angel is only for personal and non-comercial use. One of the main point in the article is to show advanced computer techniques for teaching and studying. The information in this article has been built for helping other specialist working in digital field regarding photogrammetry. Also the material can be useful for designers, engineers, archaeologists and others in their work for the publicity of ancient treasures.

THE SUITABILITY OF TERRESTRIAL LASER SCANNING FOR BUILDING SURVEY AND MAPPING APPLICATIONS

Abstract. The popularity of Terrestrial Laser Scanner (TLS) has been introduced into a field of surveying and has increased dramatically especially in producing the 3D model of the building. The used of terrestrial laser scanning (TLS) is becoming rapidly popular because of its ability in several applications, especially the ability to observe complex documentation of complex building and observe millions of point cloud in three-dimensional in a short period. Users of building plan usually find it difficult to translate the traditional two-dimensional (2D) data on maps they see on a flat piece of paper to three-dimensional (3D). The TLS is able to record thousands of point clouds which contains very rich of geometry details and made the processing usually takes longer time. In addition, the demand of building survey work has made the surveyors need to obtain the data with full of accuracy and time saves. Therefore, the aim of this study is to study the limitation uses of TLS and its suitability for building survey and mapping. In this study, the efficiency of TLS Leica C10 for building survey was determined in term of its accuracy and comparing with Zeb-Revo Handheld Mobile Laser Scanning (MLS) and the distometer. The accuracy for scanned data from both, TLS and MLS were compared with the Distometer by using root mean square error (RMSE) formula. Then, the 3D model of the building for both data, TLS and MLS were produced to analyze the visualization for different type of scanners. The software used; Autodesk Recap, Autodesk Revit, Leica Cyclone Software, Autocad Software and Geo Slam Software. The RMSE for TLS technique is 0.001 m meanwhile, RMSE for MLS technique is 0.007 m. The difference between these two techniques is 0.006 m. The 3D model of building for both models did not have too much different but the scanned data from TLS is much easier to process and generate the 3D model compared to scanned data from MLS. It is because the scanned data from TLS comes with an image, while none from MLS scanned data. There are limitations of TLS for building survey such as water and glass window but this study proved that acquiring data by TLS is better than using MLS.

THE SUITABILITY OF TERRESTRIAL LASER SCANNING FOR STRATA BUILDING

Abstract. During the recent years, the used of terrestrial laser scanning (TLS) is becoming rapidly popular because of its ability in several applications, especially the ability to observe complex documentation of complex building and observe millions of point cloud in three-dimensional in a short period. Users of strata plan usually find it difficult to translate the traditional two-dimensional (2D) data on maps they see on a flat piece of paper to three-dimensional (3D). The TLS is able to record thousands of point clouds which contains very rich of geometry details and made the processing usually takes longer time. In addition, the demand of strata survey work has made the surveyors need to obtain the data with full of accuracy and time saves. Therefore, the aim of this study is to study the limitation uses of TLS and its suitability for strata building survey. In this study, the efficiency of TLS Leica C10 for strata building survey was determined in term of its accuracy and comparing with Zeb-Revo Handheld Mobile Laser Scanning (MLS) and the distometer. The accuracy for scanned data from both, TLS and MLS were compared with the Distometer by using root mean square error (RMSE) formula. Then, the 3D model of the building for both data, TLS and MLS were produced to analyze the visualization for different type of scanners. The software used; Autodesk Recap, Autodesk Revit, Leica Cyclone Software, Autocad Software and Geo Slam Software. The RMSE for TLS technique is 0.001m meanwhile, RMSE for MLS technique is 0.007 m. The difference between these two techniques is 0.006 m. The 3D model of building for both models did not have too much different but the scanned data from TLS is much easier to process and generate the 3D model compared to scanned data from MLS. It is because the scanned data from TLS comes with an image, while none from MLS scanned data. There are limitations of TLS for strata building survey such as water and glass window but this study proved that acquiring data by TLS is better than using MLS.

3D LASER SCANNING FOR PRESERVATION AND STRUCTURAL MONITORING OF HISTORIC CALIFORNIA ADOBE MISSIONS

INTRODUCTION At the University of San Francisco Architecture & Community Design Program, the Architectural Engineering curriculum utilizes a Leica ScanStation C10 3D Laser Scanner to document historic structures and monitor their structural behavior. Some of the oldest structures in the State of California are the historic adobe missions built by Native Americans and Spanish Catholic missionaries between 1769 and 1833. California is a region of very high seismic activity, and the adobe structures have withstood significant earthquakes and other erosive or destructive forces over their lifetime. However, they are sensitive structures in need of active preservation and very few original adobe buildings remain. Working together with local structural engineers who specialize in seismic restoration of historic adobe structures, USF students have conducted laser scanning at Mission Santa Cruz and Mission San Miguel Arcángel, creating extensive 3D point cloud records, and developing architectural drawings which establish the current state of these structures for the purposes of historic preservation and structural study. Because of the delicate and irregular nature of these structures, the 3D laser scanner is the most appropriate tool for detailed yet non-invasive documentation. Completed in 1821, Mission San Miguel Arcángel suffered significant damage in the nearby 2003 San Simeon earthquake. The original adobe structure has undergone partial repairs such as banding at the top of the walls of the Sacristy. Using the 3D laser scanner, thorough scans are stitched together to create full interior and exterior 3D point cloud files, which are processed in Leica Cyclone and Autodesk Recap, and then imported into AutoCAD to create detailed line drawings of plans, elevations and sections of significant areas. Wall lean and other indicators of crack progress and deterioration are areas of special focus. With these records, a structural monitoring program has begun to document the condition of the buildings in wet seasons and dry seasons, and to determine the long-term effect of seismic restorations which have been implemented. This paper presents a detailed account of the process, pedagogical value and structural and architectural lessons learned over the course of the 3D scanning of these valuable heritage landmarks.