Application of additive manufacturing to the digital restoration of archaeological artefacts

A review of literature showed that published applications of Additive Manufacturing (AM) to digital restoration of archaeological artefacts was rather limited. This paper reports a substantial body of work that has been done in this area. It has been used to determine how AM and subsequent processes should be optimally applied, and introduces a series of process maps that have been generated to guide future practical work. The research methodology employed was predominantly action research, where the researcher undertakes practical work in a reflective manner to develop answers to specific research questions, with a combination of questionnaires and expert interviews used for validating the process maps. The results generated from the work indicated that archaeological artefacts can be characterised according to subject, material, complexity of shape, overall size, minimum feature size, and surface finish. The optimised application of AM and subsequent processes can then be specified in response to these requirements. The outputs from the research should prove to be valuable to anyone working in the field of digital restoration and fine art sculpture, particularly when digital capture of shape and the creation of physical replicas are required. The main contribution to knowledge is the characterisation of archaeological artefacts and the resultant process maps derived from this characterisation. However, the range of projects undertaken was not representative of every combination of artefact characteristics, and some requirements could not be met fully by current AM capabilities, so there remains a need for further research on process development

Optimising additive manufacturing for fine art sculpture and digital restoration of archaeological artefacts

Additive manufacturing (AM) has shown itself to be beneficial in many application areas, including product design and manufacture, medical models and prosthetics, architectural modelling and artistic endeavours. For some of these applications, coupling AM with reverse engineering (RE) enables the utilisation of data from existing 3D shapes. This thesis describes the application of AM and RE within sculpture manufacture, in order to optimise the process chains for sculpture reproduction and relic conservation and restoration. This area poses particular problems since the original artefacts can often be fragile and inaccessible, and the finishing required on the AM replicas is both complex and varied. Several case studies within both literature and practical projects are presented, which cover essential knowledge of producing large scale sculptures from an original models as well as a wide range of artefact shapes and downstream finishing techniques. The combination of digital technologies and traditional art requires interdisciplinary knowledge across engineering and fine art. Also, definitions and requirements (e.g. ‘accuracy’), can be applied as both engineering and artistic terms when specifications and trade-offs are being considered. The thesis discusses the feasibility for using these technologies across domains, and explores the potential for developing new market opportunities for AM. It presents and analyses a number of case study projects undertaken by the author with a view to developing cost and time models for various processes used. These models have then been used to develop a series of "process maps", which enable users of AM in this area to decide upon the optimum process route to follow, under various circumstances. The maps were validated and user feedback obtained through the execution of two further sculpture manufacturing projects. The thesis finishes with conclusions about the feasibility of the approach, its constraints, the pros and cons of adopting AM in this area and recommendations for future research

Three-dimensional scanning as a means of archiving sculptures

Thesis (M. Tech. Design technology) -- Central University of Technology, Free State, 2011This dissertation outlines a procedural scanning process using the portable ZCorporation ZScanner® 700 and provides an overview of the developments surrounding 3D scanning technologies; specifically their application for archiving Cultural Heritage sites and projects. The procedural scanning process is structured around the identification of 3D data recording variables applicable to the digital archiving of an art museum’s collection of sculptures. The outlining of a procedural 3D scanning environment supports the developing technology of 3D digital archiving in view of artefact preservation and interactive digital accessibility. Presented in this paper are several case studies that record 3D scanning variables such as texture, scale, surface detail, light and data conversion applicable to varied sculptural surfaces and form. Emphasis is placed on the procedural documentation and the anomalies associated with the physical object, equipment used, and the scanning environment. In support of the above, the Cultural Heritage projects that are analyzed prove that 3D portable scanning could provide digital longevity and access to previously inaccessible arenas for a diverse range of digital data archiving infrastructures. The development of 3D data acquisition via scanning, CAD modelling and 2D to 3D data file conversion technologies as well as the aesthetic effect and standards of digital archiving in terms of the artwork – viewer relationship and international practices or criterions of 3D digitizing are analysed. These projects indicate the significant use of optical 3D scanning techniques and their employ on renowned historical artefacts thus emphasizing their importance, safety and effectiveness. The aim with this research is to establish that the innovation and future implications of 3D scanning could be instrumental to future technological advancement in an interdisciplinary capacity to further data capture and processing in various Cultural Heritage diagnostic applications

Digital sculpting for historical representation: Neville tomb case study

Despite digital 3D polygon modelling applications providing a common and powerful tool-set for archaeological, architectural and historical visualisation over recent years, digital deformation sculpting tools are little used at present within the area of historical visualisation. More commonly applied within the video games and TV/motion picture industries, the intention of this research is to combine such tools and methodologies with existing scanned data and historical knowledge to remediate and re-imagine lost sculptural form. The aim would be to support both academic and public understanding of such missing artefacts. In addition, the research may promote alternative methods of prototyping within traditional stone carving industries and further provide an opportunity to critically evaluate approaches to deliberately mediated sculptural surrogates and their location within historical representation. The intended research will focus on an examination and partial re-construction of the Neville tomb at Durham Cathedral. An example of cultural vandalism, the tomb has been damaged at key moments throughout several hundred years of social and religious upheaval. It will provide the researcher with an opportunity to re-create and interpret some of the lost sculptural forms carved upon it. In addition, it affords the opportunity to further explore the use of polychrome on medieval stone carving

Replication and fabrication of crafted and natural artifacts by reverse engineering using single camera photogrammetry

Photogrammetry has been used for recording objects for well over one hundred and fifty years. Modern photogrammetry, or digital image capture, can be used with the aid of a single medium range Digital Single Lens Reflex (DSLR) camera, to transform two-dimensional (2D) images into three-dimensional (3D) Computer Aided Design (CAD) spatial representations, and together with the use of additive manufacturing (AM) or 3D Printing technology, geometric representations of original cultural, historic and geological artifacts can be fabricated using a process known as Non-invasive Reverse Engineering. Being able to replicate such objects is of great benefit to educationalists and, for example, curators; if the original object cannot be handled because it is fragile, then replicas can give the handler a chance to experience the size, texture and weight of rare objects. Photogrammetry equipment is discussed, the objective being simplicity of execution for eventual realisation of physical products such as the artifacts discussed in this thesis. All the digital photographic data in the research has been captured either with the use of a mid-range DSLR camera or a compact “point and shoot” camera. As the processing power of computers has increased and become more widely available, and with the use of user-friendly software programs it is now possible to digitally combine multi-view photographs, taken from 360° around the object, into 3D CAD representational virtual images, transforming these so they are ready for AM machines to produce replicated models of the originals. Over 50 objects were used in this research and the results documented: from the reproduction of small modern clay sculptures; 3,500-year-old Egyptian artifacts; household vases, figurines and bottles; fossils, shells and rocks, although not all successfully recreated. A variety of AM technologies have been employed, mostly monochromatic but including colour AM machines, to fabricate the models where good 3D models have been obtained. A bench-mark test was performed to ascertain the justification for the additional time and computer power required to produce ultra-high resolution digital images for the models to be fabricated on high resolution AM technology, in order to test the best possible limits of artifact reproduction. An in-depth case study on four problematic artifacts was also conducted using amongst other methods, RAW photographic images as opposed to camera ready Jpeg images; the results were analysed for comparison and conclusions were drawn

DISPLAYING DANTE’S DIVINE COMEDY MINIATED MANUSCRIPTS IN EXHIBITIONS

Ancient manuscripts are part of many collections belonging to historic libraries and museums: due to their fragile nature and to the difficulties to display most of their contents during exhibitions, their study is often complicated for scholars who also need generally special permissions to examine them, mostly for a limited time window. Beginning from these premises, this paper introduces the outcomes of the digital replication and presentation of three manuscripts related to Dante’s Divine Comedy, as proposed on a real exhibition, “Dall’Alma Mater al Mondo. Dante at the University of Bologna”, held in 2021. Some of the principles related to the production of their replicas and the fruition of their contents through dedicated applications targeted to visitors and scholars are presented, with care to the reproduction of details such as the ability to explore 3D replicas of detailed elected pages or to browse many of them on dedicated touch screens

An investigation into 3D printing of osteological remains: the metrology and ethics of virtual anthropology

Three-dimensional (3D) printed human remains are being utilised in courtroom demonstrations of evidence within the UK criminal justice system. This presents a potential issue given that the use of 3D replicas has not yet been empirically tested or validated for use in crime reconstructions. Further, recent movements to critically evaluate the ethics surrounding the presentation of human remains have failed to address the use of 3D printed replica bones. As such, this research addresses the knowledge gap surrounding the accuracy of 3D printed replicas of skeletal elements and investigates how the public feels about the use of 3D printed replicas. Three experimental studies focussed on metrology and identified 3D printed replicas to be accurate to within ± 2.0 mm using computed tomography (CT) scanning, and to within ± 0.2 mm or to 0-5% difference using micro-CT. The potential loss of micromorphological details was also examined and identified that quality control steps were key in identifying and mitigating loss of detail. A fourth experimental study collected data on the opinion of the public of the use of 3D printed human remains in courtroom demonstrations. Respondents were broadly positive and considered that prints can be produced ethically by maintaining the dignity and respect of the decedent. A framework that helps to assess ethical practices was developed as well as an adaptable pathway that can assist with assessing the quality and accuracy of 3D prints. The findings from this research contribute to an empirical evidence base that can underpin future 3D printed crime reconstructions and provides guidance for creating accurate 3D prints that can inform future practice and research endeavours