Introduction/Aims:
3D scanning and 3D printing have opened up a range of new opportunities in the museum sector. Although the use of 3D scanning in museums is still in its infancy, applications include visitor engagement opportunities, the improved digitisation of records, and aiding in the preservation and conservation of museum objects or even entire archaeological sites. It is now possible to study condition changes over time in far greater detail than 2D images will allow, and 3D printing can even be used to repair or reproduce damaged or lost artefacts. In 2017, two damaged busts from the ancient city of Palmyra were repaired using 3D printing after being damaged in an attack by ISIS[1]. 3D scanning also raises the opportunity to create virtual museums or exhibitions, improving access to cultural heritage. These virtual models can also be incorporated into existing displays allowing visitors a closer and more tactile experience than ever before. There is also the potential for use in augmented or virtual reality settings[2].
In this inaugural 3D scanning project at the Western Australian Museum, our aim was to experiment with this new technology, to explore its limitations, and determine how it can be used in our context. As part of the WA Museum’s New Museum Project, 20 objects were chosen to be scanned using the EinScan Pro+ 3D scanner and the Shining 3D software.
Methods:
Two main scanning modes were utilised doing this process; the fixed turntable scan and the rapid hand held scan. The turntable mode is more suitable for small objects (approximately less than 30cm in diameter), as the object needs to fit onto the mechanism to be rotated. As it rotates, the scanner, which is set up on a tripod before the turntable, is able to capture the features of the object from all angles. Depending on the shape of the object, multiple scans may be required, whereby the object is reoriented on the turntable in order to capture data from its every angle and face.
In rapid hand held scan mode, the scanner is moved over the faces of the object, rather than the object being rotated before it. Once again, multiple scans capturing the object at varied orientations may be required to capture the whole object. This mode allows for the scanning of medium to large objects as the limiting factor is not the size or strength of the turntable, but rather the length of cable attaching the scanner to the computer.
In both modes, the scanner will likely capture excess data of features surrounding the object. After each scan, the program enters an editing stage whereby unnecessary data can be selected and deleted, and the scanning process can continue.
Once having captured the object in a 3D tracing, the 3D object is meshed and can be saved in either a watertight or un-watertight format. Un-watertight format saves the object exactly as it has been rendered, while the watertight format fills in any holes that maybe be present. It is necessary to use a watertight mesh for 3D printing.
Results and evaluation:
Some of the main issues we faced when undertaking this project were long processing times when meshing scans, not being familiar with the equipment and software, and not enough information and support to learn more about the equipment and software. We especially felt a lack of supporting information in relation to using the technology in the museum context, as many of the techniques typically used to improve the quality of a scan are not viable options when working with registered objects. As an example, objects with dark, reflective or transparent surfaces are often sprayed with powdered aerosol sprays to improve the scanning conditions. Without this option we relied on adjusting lighting and exposure to reduce glare and light scatter. This was largely a trial and error process which was very time consuming and, at times, unsuccessful.
One of the selling points of the Einscan pro+ is the ability to use tracking markers in collaboration with a HD scan mode. However, this setting was unsuitable for our project as we could not place adhesive rounds on to the museum objects and colour capture is disabled. As much of the value of the final 3D model relies on capturing the texture, colour, and shape, this setting was largely unexplored in our experimentation.
In order to produce successful scans, we were limited to objects that are not reflective, are lighter in colour, do not have repetitive patterns and are easily handled. We faced great difficulty with ceramics and fabrics that featured repeating patterns, as the software did not seem able to differentiate between areas with the same pattern, and frequently lost track of which area was being scanned. At times this resulted in the inability to continue scanning the object, while at other times resulted in the deformity of the final 3D model when the technology eventually recognised the pattern, but at a completely different location of the object. It was also difficult to capture data from within the folds or creases of some objects, resulting in actual holes in un-watertight meshes.
As well as experiencing difficulties in the scanning process, we found the software had a habit of randomly generating junk data after the editing stage, which manifested as lumps or outgrowths on the final 3D model. Despite multiple attempts at trial and error, and deleting the generated data several times, we were unable to find the cause of the problem, or a way to prevent it. It might be possible to delete the excess data from the 3D model using 3D model editing software such as Zbrush, or even, potentially, using photoshop. We did not experiment with these avenues at this time, but they are worth exploring in the future.
Overall, our findings from this project are that 3D scanning has enormous potential for use in the museum sector. As more exploratory work is done in this area, and the results are shared and discussed, the process will become better understood and results will improve. It is our understanding that in order to produce quality scans that could be used in exhibitions or published online, it would be necessary to use higher quality scanning equipment.
We would like to acknowledge the Foundation for the WA Museum’s Minderoo Grant, for supporting this project.
References:
[1]https://www.3ders.org//articles/20170217-preserving-syrias-heritage-3d-p…
[2]https://maas.museum/inside-the-collection/2016/10/21/3d-scanning-icons-from-the-maas-collection/
Further Reading:
https://3dscanexpert.com/shining-3d-einscan-pro-3d-scanner-review/