3D Laser Scanner Survey and 3D Printed Model Production of the Former Kakogawa Library
― Preservation and Utilisation of Historic Buildings through Digital Archiving ―
Hironori Ohtoshi, Tutor, Department of Architecture, Hyogo Prefectural Toban Technical High School
1. Background of the Project
This project began after our school was selected as a "Smart Vocational School" by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) in 2021, through the development of digitalisation-compatible industrial education equipment, with the aim of realising modern and enhanced vocational education. This provided the opportunity to introduce a 3D laser scanner, which was used for the digital archiving of the former Kakogawa Library in Kakogawa City, Hyogo Prefecture (Figure 1)
The former Kakogawa Library was designated as an important cultural asset for landscape formation by the Hyogo Prefecture in 2008 and was used as a public library until 2021. However, after more than 80 years since its construction, the building has deteriorated, and concerns have been raised about its seismic strength, leading to ongoing discussions regarding its future. Additionally, the building was originally constructed as the "Kakogawa Town Hall" and is also known as the site where the author Yukio Mishima underwent his conscription examination during the war while in evacuation (it is said that he was examined under the pine tree next to the town hall, Figure 2).
Figure 2: The pine tree, still existing with the same branching structure as when Yukio Mishima underwent his conscription examination.
As part of their research project, eight third-year students from the Architecture Department's "FabLab Studio Toban" conducted a survey using a 3D laser scanner and recorded the precise shape of the former Kakogawa Library. This report summarises the process from the surveying to the creation of a 3D printed model and discusses the results achieved.
2. Purpose of the Project
To record the architectural shape of the former Kakogawa Library using a 3D laser scanner and preserve it as digital data.
To create a 3D printed model based on the acquired point cloud data and use it for architectural education and awareness-raising activities for local residents.
To provide an opportunity to learn and practise methods of cultural heritage preservation using digital archiving technology.
3. Implementation of 3D Laser Scanning Surveying
3.1 Equipment Used
3D Laser Scanner
・ Leica RTC360
Data Processing (Point Cloud Processing Software)
・ Leica Cyclone REGISTER 360
・ Autodesk ReCap
3.2 Surveying Procedure
1. Site Survey and Preparation
o Investigated the exterior and interior structure/decorative design of the former Kakogawa Library and determined the scanner installation positions (instrument points) (Figure 3).
o Considered the weather and surrounding environment to set the optimal measurement conditions (Figure 4).
3: Tablet screen for field processing using Leica Cyclone FIELD 360
4: Orthorectified point cloud image showing the instrument points and links for the exterior survey
2. Conducting the Scan
o Measured the exterior of the building, including the roof, from all 360° directions to capture precise point cloud data (Figure 5, left).
o Scanned the interior space, including the ceiling void on the second floor (Figure 5, right), completing measurements at a total of 150 locations. The captured point cloud data reached approximately 300 million points (Figure 6).
Figure 5: Tablet screen displaying scan data
Right: Rooftop where water leakage was identified
Left: Ceiling void on the second floor, retaining remnants of the original theatre arch ceiling from the time of construction
Figure 6
Top: Second-floor foyer featuring a large arch window with stained glass designed in the Art Deco style
Bottom: Point cloud representation of a room renovated into an open-access library
3. Data Integration and Processing
o Using Leica Cyclone REGISTER 360, the point cloud data from each measurement point was integrated (Figure 7).
o Using Autodesk ReCap, unnecessary noise was removed, a 3D model was created,
and data consistency was verified (Figure 8).
Figure 7: Point cloud data integration using Leica Cyclone REGISTER 360
Figure 8: 3D model of the former Kakogawa Library created from the integrated point cloud
4. Creation of 3D Printed Model
4.1 Data Conversion and Editing
Based on the point cloud data, key structural dimensions were measured, and CAD drawings were created (Figure 9).
Figure 9: CAD drawing of the former Kakogawa Library created based on point cloud data
Converted to STL format for 3D printing (Figure 10).
Figure 10: Importing the STL file into slicing software (Ultimaker Cura) and converting it to G-code.
4.2 3D Printing
Equipment used: Ultimaker 2+ Extended (FDM method, Figure 11)
Figure 11: Components 3D printed using bio-plastic (PLA) with consideration for the environment.
Each component, printed in sections, was post-processed (removal of support material, surface sanding, filler treatment, and painting) and finally assembled (Figure 12).
Figure 12: Sanding process to smooth the surface of the 3D printed components.
5. Results and Discussion
The students acquired practical skills in 3D laser scanning technology and data processing, gaining valuable experience in learning the significance of cultural heritage preservation. This initiative has been featured in various media (Figure 13).
Figure 13: Kobe Shimbun, 24th July 2022, Morning Edition, Page 26
The usefulness of the 3D printed model was confirmed for architectural education and as display material (Figures 14 and 15).
Figure 14: Introduction of the 3D printed model of the former Kakogawa Library to junior high school students at the Open High School event.
Figure 15: Exhibition scene at the Architecture Department's exhibition (left: poster, right: display).
The detailed 3D model of the former Kakogawa Library was digitised and the point cloud data was donated to the Kakogawa City Construction Department's Building Maintenance Division (Figure 16).
Figure 16: Display and viewing of point cloud data using the TREND-POINT viewer (enabling measurement of distance and volume, and the inspection and analysis of cross-sectional shapes).
Donated the 3D printed model to Kakogawa City and exhibited it at the Kakogawa Library (Figure 17).
Figure 17: Kobe Shimbun, 4th February 2023, Morning Edition, Page 26
18: Display of the
6. Future Prospects
Consider the creation of VR/AR content based on point cloud data (Figures 19 and 20).
The same methods will be applied to other local cultural heritage buildings, aiming to expand the digital archive.
Collaboration with the Kakogawa City Cultural Heritage Research Center has been confirmed.
7. Summary
Through this project, we carried out practical cultural heritage preservation using 3D laser scanning and 3D printing technologies. While re-recognising the importance of digital archiving, we aim to continue contributing to the preservation and utilisation of local historical buildings. Additionally, through this initiative, we were able to gain confidence in establishing a curriculum that teaches the latest construction technologies through the practical application of digital archiving of cultural heritage, with a focus on the digital transformation in construction.
A digest of the project and a retrospective video
Project Period: 1st April 2022 – 31st March 2023
By scanning the following QR code, you can watch a digest of the project as well as a retrospective video from the students. Please be sure to check it out.
Location: Former Kakogawa Librar
Participants: Hyogo Prefectural Higashi Harima Technical High School, Department of Architecture, FabLab Studio Students: 8
Instructor: Hironori Ohtoshi
FabLabStudio 2022 members
Acknowledgements
I would like to express my sincere gratitude to the Kakogawa City Board of Education for granting permission to use the Former Kakogawa Library for this research project, and to the Kakogawa City Central Library for attending the on-site training sessions. I also wish to thank the Kakogawa City Construction Department's Maintenance Division for providing the architectural drawings, as well as the Toda Mirai Foundation for their generous support in promoting education related to construction. My deepest appreciation also goes to all those who cooperated with this project.
