Keywords

1 3D Documentation of Finds

In archaeology, the visual documentation of finds has always played a decisive role in scientific discourse. Since handmade technical drawings always require a great deal of time and money, while the image obtained is always subjective, there has long been an interest in finding more efficient, cheaper and more objective technical solutions to optimise graphical documentation (Reuter and Innerhofer 2016). Even technical photography has been able to offer only limited progress in this area, due to the uncontrollable information density of photographs – individual geometric surface features are always covered by the overall texture of the photographed object. In addition, the risk of distortion and non-specified dimensional accuracy must always be compensated for (Innerhofer and Lindinger 2010).

For this reason, the Archaeological Heritage Office of Saxony (LfA Saxony) began to take an interest in the potential of 3D documentation for object-based science more than 15 years ago (Lindinger 2007; Lindinger and Hörr 2008). At that time, the industrial applications of 3D scanners were already well established and an evaluation was conducted to determine to what extent their capabilities could be used to address archaeological questions. With the acquisition of a Konica Minolta VI-910 laser scanner and the establishment of a fixed recording studio with light tent and lighting, as well as a workflow for the preparation of the 3D data (Kießling 2006), the continuous scanning of finds began. In time, the laser scanner was supplemented by two structured light scanners, which provide much more precise measurement results and present the scanned objects in considerably higher resolution (AICON smartSCAN-HE 5 MP and 8 MP; Naumann 2009) (Fig. 3.1). A further device, a mobile handheld scanner (Artec EVA™), supplements the laboratory equipment, especially when it comes to external scanning for which a high degree of flexibility and mobility is required, for example when performing detailed 3D scans in the confined galleries of medieval mines (Jahn 2013; Göttlich 2014; Reuter and Nauck 2015). All 3D scanners are equipped with colour sensors, so that the RGB data is automatically available without the need for additional recording and can be used as textures. Due to the high degree of automation and the efficiency of industrial measurement systems, Structure-from-Motion (SfM) is rarely used for the 3D digitisation of finds. Instead, it is employed for excavations or for the documentation of the archaeological features of mines.

Fig. 3.1
A photo of a 3-D scanner and its supplements.

The Konica Minolta VI 910 laser scanner, the two AICON smartSCAN-HE structured light scanners and the Artec EVA™ handheld scanner in the 3D laboratory of the LfA Saxony. (LfA Saxony)

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Additionally, the program TroveSketch was developed in cooperation with the Chemnitz University of Technology, Chair of Graphic Data Processing and Visualisation, by means of which the 3D models, especially of archaeological objects, can be evaluated in a few intuitive steps (Hörr 2005, 2006, 2011). In this way, 3D models can be automatically measured and aligned with different algorithms. In addition to the usual values, such as height, width or volume, other dimensional relationships are also determined, which, after being exported to lists, can provide the basis for, e.g., training an AI application, as shown in the figure below, using the example of a pot from the Neolithic well at Altscherbitz (Fig. 3.2). Emphasis was placed on the visualisation of the 3D models using different real-time 3D shaders, in order to display the scans either with the colour information or specifically in different grey or false-colour renderings, so that individual surface features, such as decorations or traces of use, can be brought out more clearly. Integrated functions for the cylindrical or polar unwrap** of rotationally symmetrical bodies, such as vessels, greatly simplify and accelerate the process of documenting complex surrounding ornaments. In a subsequent work step, the profile can then be extracted to the respective 3D model by means of freely definable sectional planes and exported as a vector graphic, enabling the generation of a complete data set of object views and associated profiles or cross-sections in a short time and with just a few clicks. The true-to-scale export of the graphics is done using common data formats. This guarantees a consistently high image quality and, for the first time, makes the find representations objectively comparable. Over the years, TroveSketch, which has undergone further stages of development, has established itself as the central interface for 3D documentation at the LfA Saxony.

Fig. 3.2
A screenshot of the Trove Sketch web page presents a 3 D view of a baggy pot with its measurements listed below.

The documentation program TroveSketch with a baggy pot from the Neolithic well at Altscherbitz. The picture shows the results and their visualisation of the automatic measurement. (LfA Saxony)

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Because its 3D documentation is not only accurate, but also highly effective, TroveSketch is often used by students for scanning and data processing, after a short training period, in order to document examination material for theses and dissertations (e.g. Richter 2013; Schmalfuß 2019).

2 Examples of Applications

On the basis of the first experiences with 3D documentation and a growing number of scanned objects, a funded research project was able to test and discuss the potential of automated classification of Late Bronze Age ceramics using 3D models (Brunnett et al. 2005; Hörr 2011; Hörr et al. 2011, 2014). The measurements and dimensional relationships of Bronze Age vessels obtained with the help of TroveSketch made it possible to classify, with a high degree of probability, precisely those shapes that had been worked out intuitively by scientific analysis using machine-learning methods.

In light of the excavation of the Neolithic well at Altscherbitz (a district in Northern Saxony) from 2008 to 2010, the scanning of archaeological waterlogged wood became a focal point for work (Elburg 2010; Tegel et al. 2012; Elburg et al. 2014; Schell and Herbig 2018). An effective workflow involving excavation, cleaning and 3D scanning made it possible to create a virtual reconstruction of the well while the excavation was taking place. This provided significant support to the excavation team’s work and, through the migration of additional data, an important foundation for the archaeological documentation, as shown in the illustration (Fig. 3.3), with the cross-section of the virtual reconstruction showing the well box, the layering and the scanned vessels (Elburg et al. 2014). This enables the wooden finds to be studied while they undergo a lengthy conservation process.

Fig. 3.3
A graphical presentation of a layered well box.

Cross-section of the virtual reconstruction, with well box, layering and the scanned vessels. (Elburg et al. 2014)

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Within the framework of several Interreg projects funded by the EU and carried out in cooperation with Czech partners, the experience from the excavation of the well could be exploited and further developed (e.g. Göttlich and Reuter 2013; Schröder 2018). A closely coordinated workflow between the excavation team, the conservation department and the 3D laboratory made it possible to digitise and document several thousand wooden finds. While the original wooden objects are undergoing a conservation process that will last several years, the 3D data can be used for research studies and publications. The combination of survey data, SfM and the high-resolution 3D scans makes it possible to produce detailed reconstructions, which provide a completely new approach to the excavation findings in medieval mines. A giant reversible waterwheel (fifteenth/sixteenth century), called a ‘Kehrrad’ in German, was found in Bad Schlema (a district in Sächsische Schweiz Osterzgebirge) at a depth of more than 30 metres and could be documented and reconstructed in detail using these methods (Drechsler et al. 2018). The massive dimensions of the wheel, with a diameter of 12 metres, made it highly challenging not only to document the excavation, which lasted more than two years, but also to manage the large amounts of data (e.g. photos, SfM, 3D scans). The targeted generalisation of the data using reverse-engineering tools, for example, reduced the high-resolution data of the structured light scanners, in order to integrate it into a virtual reconstruction (Fig. 3.4). The graphic shows the scene rendered in Autodesk 3ds max with simplified geometry blended with 3D data from the lower area, while the red circle represents the original diameter of 12 metres. The complex underground situation can thus be examined not only at the level of the finding as whole, but also at the object level by means of the original, uncompressed high-resolution 3D scans.

Fig. 3.4
A 3-D illustration of a water wheel generated on an Autodesk 3 ds max scanner.

An Autodesk 3ds max rendered scene with simplified geometry blended with 3D data from the lower area. The red circle illustrates the former diameter of 12 m of the waterwheel. (LfA Saxony)

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The mass of 3D data from archaeological finds provides the data basis for further comparative measurements to detect and quantify geometric deformations of the wooden finds that inevitably occur during the conservation process, which employs impregnation and freeze-drying. Using Geomagic Studio or other appropriate software, two best-fit-aligned 3D models of an object scanned before and after conservation are compared. The result of the 3D comparison is visualised as a colour-coded texture, in which blue areas indicate shrinkage and red areas swelling (Fig. 3.5). Additional volume measurements can be used to determine the dimensions of shrinkage or swelling. These comparisons document all changes caused by internal or external influences on the object in relation to the previous measurements (Schmidt-Reimann and Reuter 2015). The results show the success of the conservation process and can serve as a basis for discussion, in order to optimise the conservation procedure if necessary. Continuous monitoring by repeated measurements is possible at any time and can be used for other objects by combining various other non-invasive, optical measuring methods (Rahrig et al. 2018).

Fig. 3.5
A screenshot of the Geomagic Studio 2013 presents the menu for objects, spectrum, and statistics on the left and two 3-D images of a wooden plank on the right.

Deformation measurement of a wooden plank in Geomagic Studio. The point distances between the aligned reference model (original) and the test model (conserved) are projected as a texture onto the surface of the reference model with false colours (blue: shrinkage; red: swelling). (LfA Saxony)

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Especially with the structured light scanners, the resolution of the 3D models of about 20 μm is so high that the 3D scans can be used for high-precision surface analyses. In particular, the quantitative documentation of traces of use opens up new research possibilities for reconstructing the history of archaeological objects. By way of example one could cite the evidence of continuous wear on a die of Varus on countermarked Roman coins from Augustan times (Tolksdorf et al. 2015, 2017). The measurement of characteristic surface features of the countermarks and the computerised classification of these features using statistical methods made it possible to develop a chronology within the test series. The figure shows the comparison of the scanned imprints made by dies in relation to edge sharpness, height and the surface quality of the embossing and changes to the inner surfaces of letters (Fig. 3.6) that, in conjunction with the origin of the coins, makes it possible to establish a plausible movement profile for Varus and his troops.

Fig. 3.6
4 columns. First, 3 stamps. Second, angle-to-plane comparison of the 3 countermark stamps. Third, 3 embossed elevations of letters. Fourth, the inner areas of letters A and R.

Comparison of the scanned imprints made by dies with regard to edge sharpness, height and surface quality of the embossing and changes to the inner surfaces of letters. (Tolksdorf et al. 2015)

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With the initial operation of a second structured light scanner, which is configured for small objects, a separate workflow was developed to scan coins, in which the very high-resolution 3D models on the front and back are mapped with additional macro photos captured by a full-frame camera. Given the rate of around 11 scanned coins per day, there are more efficient methods for digitising large quantities of coins, but these provide two-dimensional or at most 2.5-dimensional data. For example, the State Office for Heritage Management and Archaeology in Halle (Saale) employs Reflectance Transformation Imaging using an RTI-Dome to digitise and classify huge quantities of coins in high resolution. This procedure enables the reflection characteristics of the coin to be accurately captured and visualised in high resolution (Trostmann et al. 2019). However, what is missing here is precisely the third dimension that makes advanced analysis possible, as in the Varus project shown above. For this reason, the slower process of a complete 3D scan will be used in order to fully exploit the potential of the 3D data in later projects.

Coins, jewellery and flint can have shiny surfaces or be partially transparent. Ideally, these surfaces are coated with a spray to make scanning possible. In 2018, the LfA Saxony carried out investigations of various substances as part of a final thesis written in conjunction with the Dresden University of Applied Sciences (HTW). Suitability could be proven by means of recent test objects: chemical analyses of the compatibility of these substances on real archaeological surfaces of the finds are pending (Reuter et al. 2020). Similar problems occur when scanning waterlogged wood, since it is strictly forbidden to dry the surfaces or even to apply a coating. In these cases, it is necessary to consider whether the increased noise behaviour is acceptable or whether other documentation methods should be chosen. That said, experience shows that the higher information content of the 3D models compared to conventional digital photos is nevertheless clearly outweighed by slightly reduced data quality.

The documentation work that has been ongoing for many years and several parallel projects have resulted in the availability of around 24,000 3D-digitised archaeological objects from Saxony as of mid-2020, as well as finds from outside Saxony resulting from collaborations with archaeological institutions from neighbouring areas (e.g. May 2014).

3 Data Management

The management of 3D data during operation represents a major challenge. Each measurement initially generates raw data, in the form complex folder structures with a large number of proprietary, scanner-specific data formats, rather than individual files, as can be seen in the example of the comparison of the raw data from the AICON smartSCAN-HE and the Artec EVA™ (Fig. 3.7). Currently, all documentation data includes about 10 terabytes of storage space, which is stored on the in-house data server and backed up using suitable backup systems. For long-term archiving, the LfA Saxony will use the ExLibris Rosetta system, which currently offers only very limited support for 3D data formats and raw data and which will initially be used for other official documentation. Due to the at times very long working periods, old data is regularly requested, so that the data is currently stored, backed up and made available for direct access, but not archived using electronic long-term archiving.

Fig. 3.7
A table compares the raw data extracted from 2 scanners.

The comparison of the raw data from the scanner of the AICON smartSCAN-HE and the Artec EVA™. There are no similarities. (LfA Saxony)

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Thus, it is also possible to reprocess the 3D models with different parameters at a later date or to use the raw data for texture map** to compressed 3D models. Finally, the 3D models are exported from this recording data as Polygon File Format (*.PLY) and Wavefront (*.OBJ). These open file formats developed in the 1990s are widely used and can be read and processed by almost all 3D programs. The data servers now store 3D data from over 15 years of activity. Thanks to the consistent use of PLY and OBJ files, all 3D models can still be used and processed without any problems. However, the usability of the original raw data and measurement projects will be limited or even impossible when the proprietary scanner software is no longer used. The goal is to keep the required software running as long as possible. At the moment, LfA Saxony has not yet found a solution to this, but a strategy must be developed for dealing with the end of support for this software, as well as for the 3D scanner itself. The strategy must react to the constant developments and especially to market-driven changes.

4 Knowledge Transfer

Besides documentation, surface analysis, monitoring and the reconstruction of features, another important application of 3D data is the multimedia visualisation and presentation of 3D models. For a number of publications, apart from the large subject area of 3D documentation in the form of technical illustrations, the images used are no longer real photos, but rendered computer graphics (e.g. Smolnik 2014). Rendered graphics can be produced independently of a given time and location, which would be hardly or not at all possible with original objects in exhibitions or undergoing conservation, as shown by the rendered image of the grave goods of a burial (stroke pottery culture 5000–4500 BC) from Dresden-Nickern that can be seen in a permanent exhibition (Fig. 3.8). The possibilities of 3D printing have also been tested, the best examples being applications in museums. For the permanent exhibition of the State Museum of Archaeology Chemnitz (smac), for example, large exhibits, such as the Tumba of Wiprecht von Groitzsch, were produced in the original size using this process (Wolfram 2014, 186 Fig. 2; Reuter and Nauck 2015) and 3D modelling was used for object assembly (Wolfram 2014, 102 Fig. 24). In the context of museum business, replicas based on 3D printing are used for barrier-free access. The almost arbitrary scaling of 3D models allows objects to be significantly enlarged or shrunk for illustrative purposes, in order to make them more ‘comprehensible’. For example, a scaled-down 3D print of the Tumba of Wiprecht von Groitzsch is being presented at the Chemnitz State Museum of Archaeology in order to enable visually impaired visitors to experience the exhibit (Fig. 3.9).

Fig. 3.8
A photograph of 2 pots, a bowl, and 3 elongated tools.

Rendered image of the grave goods of a burial (stroke pottery culture 5000–4500 BC) of Dresden-Nickern. (Funke et al. 2020)

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Fig. 3.9
A photograph of a woman touching a 3-D print of the Tumba of Wiprecht von Groitzsch.

A scaled-down 3D print of the Tumba of Wiprecht von Groitzsch is used in the State Museum of Archaeology Chemnitz to make the exhibit accessible to visually impaired visitors. (LfA Saxony).

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The complete 3D reconstruction of the abovementioned, approximately four-metre-high preserved linear band ceramic well at Altscherbitz, which is part of the site documentation, served as a test object for applications of virtual and augmented reality. For the VR headset Oculus Rift, the model of the Neolithic well was placed in a virtual room, which can be explored by means of user interaction and a controller (Reuter et al. 2017). In cooperation with Microsoft, a simplified 3D model of this well (ibid.), as well as other exhibits from a more than 40-metre-long showcase, could be ported to the device, enriched with additional information and visualised. (Fig. 3.10). In this augmented-reality – or more accurately mixed-reality gadget – the model is projected onto the semi-transparent glasses, seems to hover in the room and can be viewed interactively. Particularly in these applications, consideration must be given to data reduction. Techniques from game design, such as normal map**, should be given more attention, in order to convert the highly compressed 3D models vividly even on limited hardware.

Fig. 3.10
A photograph of a showcase. It has several urns, statues, frames, and other intricate things arranged in layers. A woman wearing a headgear looks at the showcase.

The exhibits from a 40-metre-long showcase in the smac are enriched with additional information on the Microsoft HoloLens. (LfA Saxony)

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5 Website Archaeo | 3D

In view of the great potential of 3D data for the most diverse presentation possibilities, it was obvious that visualisation on the Internet was considered at an early stage – but as far as possible a largely ‘barrier-free’ one (Coburger et al. 2020). Starting from around 2010, 3D data could only be displayed with special 3D software or plug-ins for Internet browsers. With the establishment of the HTML5 standard during this period and the increasing implementation of the free JavaScript programming interface WebGL for the visualisation of 3D content in browsers, a possible solution to this requirement became apparent around 2013 (Coburger 2013). These considerations led to the creation of a comprehensive specification sheet in which the content and technical requirements for the presentation of archaeological objects on a 3D website were formulated. At the same time, however, it became clear that there was still considerable need to develop the presentation of 3D content in browsers and that the problem of transmitting relatively large amounts of 3D data via streaming was not yet fully resolved. Broadband penetration in the area of terrestrial and, above all, mobile data connections in Germany had, at the time, often not yet reached the level required to enable the smooth presentation of these data packets.

In order to keep the cost risk low in view of the many imponderables and to get the project going step by step, it was decided to draw on a pre-existing cooperation with the state-certified university Fachhochschule Dresden (FHD), particularly the Faculty of Design, for the implementation. In the winter semester 2017/2018, the design of the website was developed in the seminar ‘Interface Design’. In a user-centred design process, the students developed four comprehensive designs over the course of the semester, in which, starting from a conception of possible personas, all design elements, including typography and the colour concept for the pages and navigation, were created. Subsequently, all the proposals were evaluated and the winning proposal (Kim et al. 2018) was enriched and optimised with elements taken from the other three working groups (Böhm and Lambracht 2018; Haustein et al. 2018; Slavny et al. 2018) in around spring 2018 (Fig. 3.11). In the following semester, the programming was done in the framework of the seminar ‘Basics of Web Development’ at the Department of Media Informatics at the FHD. The online portal that was developed is based on the content-management system WordPress and uses the library Three.js to display the 3D models. This library offers a simplified use of WebGL, in which basic functionalities, such as displaying meshes, loading models, light effects or textures/point colours, are encapsulated in functions using JavaScript syntax, which reduces the programming workload in comparison to the low-level 3D graphics API. In order to obviate the need to manually input the archaeological metadata into WordPress, it is exported from the 3D database of LfA Saxony and imported into WordPress using WP All Import. Since the metadata is not directly transferable, it is converted using PHP scripts during this process. The plug-in Advanced Custom Fields (ACF) offers a simple way of structuring the find and metadata in WordPress and integrating it into the posts and pages.

Fig. 3.11
A screenshot of the welcome page of the Archaeo 3-D website. It has 5 tabs at the top and the details of the page on the left in a foreign language. A photo of 2 pots and a bowl is in the center.

Welcome page of the website Archaeo | 3D. The content is available in two languages. (LfA Saxony)

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The data generated by the 3D scanners, with their sometimes extremely high resolutions, exceed the current technical possibilities of web-based visualisation. For this reason, the original 3D models must be compressed, in order to reduce the amount of data they contain. This is inevitably accompanied by a sometimes severe loss of display quality, which must be weighed up and ultimately accepted. With the help of a test series of 3D models reduced in different ways, an upper data limit of one million polygons was found, which offers a compromise between loss of resolution, display quality and performance for the planned website. The data reduction is performed using powerful algorithms in the program Geomagic Studio. Subsequent texture map** using the stored raw data transfers the original colour information to the simplified 3D model. Finally, the reduced 3D models are converted into the streaming file format NXS using Nexus-3D. After testing various options, the choice was made to use the tools provided by Nexus for converting PLY and OBJ files. These tools create sequences of increasingly coarse mesh partitions and simplify the geometry of the 3D model (Nxsbuild). The file sizes usually lie between 30 and 40 MB, due to the previous compression of the original models, but smaller file sizes of up to 5 MB are also possible for smaller objects, some of which do not need to be reduced at all and can be published in the original resolution.

The final version was produced by the company DigitalKonstrukt and the website was published in spring 2020 at www.archaeo3d.de (e.g. the ‘reconstructed grave of Niederkaina’ or the ‘Kumpf of Altscherbitz’). All common Internet browsers, except Internet Explorer, are supported. The consistently responsive programming makes it possible to use the website on a large number of mobile devices (Fig. 3.12). Initially about 100 finds were published and this number will steadily increase. In the future, additional functionalities will be integrated, such as a measuring function or the possibility to interactively manipulate the light source in the 3D view. For the visitor, each 3D model (i.e. each object) is linked to a unique ID number, so that all found objects remain citable via an individual and permanent web address.

Fig. 3.12
A screenshot of the welcome page of the Archaeo 3-D website from a smartphone. It has details in a foreign language and a photo of a pot in the center.

Thanks to the responsive programming, the content adapts dynamically to the display size of smartphones. (LfA Saxony)

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The data pool can either be explored via a map display or searched using a variety of filter options. The 3D model can be viewed interactively on the corresponding object pages. The user can choose to view the objects without colour information, in order to make surface details more recognisable. Each find is supplemented with the corresponding archaeological and technical metadata. The archaeological address, finding place, dating and cultural classification of the object, along with its material and category, form the core of the data set. The description of the object, as well as all information about the site, features and context of the find, the technical metadata, the literature and information on ownership and usage rights, can be found in part under expandable menu items. If there are several related objects, they are shown in the lower area with thumbnails and can be called up directly, as seen in the example of the detail page of a bark-decorated deep bowl with the 3D window on the left and the corresponding metadata on the right (Fig. 3.13). The ‘Archive’ page lists the thumbnails of all the objects presented on the website, while the left-hand column allows filtering across many categories. The subpage ‘3DLaboratory’ provides comprehensive information on 3D documentation at LfA Saxony. A glossary of archaeological terms enables non-professionals to look up specialised words they may be unfamiliar with.

Fig. 3.13
A screenshot of the details page of the Archaeo 3-D website. It has a 3-D photo of a bowl on the left and its description on the right.

The detail page of a bark-decorated deep bowl with the 3D window on the left and the corresponding metadata on the right. (LfA Saxony)

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The technical metadata is currently being stored in the in-house 3D database. This database is based on the Archaeology Documentation and Information System of the LfA Saxony and was extended to meet the requirements of describing find objects and 3D data. In addition to the location information, which, through the administrative district, also makes it possible to link to the coordinates for presentation on a map, the archaeological address focuses on the location and type of site, the context of the features and finds, and the detailed description of the object, including dating and cultural classification. In addition, bibliographical references and proof of ownership are available, along with some technical metadata, which is intended to document the 3D acquisition. These include the sensor with the size of the measuring field and the measuring method. The resolution of the original scan can be read from the size of the point distance. There do not currently exist standards for the acquisition of technical metadata in relation to documentation with 3D scanners, as is usual for digital cameras with EXIF data. Therefore, this information represents a first suggestion for addressing this problem, although the automatic transfer of comparable manufacturer-specific parameters during measurement would be desirable. A comparison of the parameters in the three scanner applications used at the LfA Saxony (i.e. AICON OptoCat, Artec Studio, Geomagic Studio) shows that there are no manufacturer-specific comparable data or parameters, apart from the basic information about the manufacturer, sensor, measuring field and, finally, the resolution of the 3D model.

With this new website, the LfA Saxony has gained a powerful and expandable presentation and publication portal. If one compares the platform with traditional means of communication, such as publications or museum exhibitions, whether in analogue or digital form, it is clear that completely new paths are being taken here that allow for more direct and significantly more interactive access to the archaeological objects.

6 Fifteen Years of 3D Documentation

The systematic implementation of industrial measuring systems has significantly expanded the possibilities for archaeological documentation at the LfA Saxony. The expertise gained is maintained by the fact that the department is no longer a project, but is permanently integrated into the national office.It cannot be denied that the acquisition of several modern 3D scanners and the permanent operation of the scanner workplaces requires considerable financial resources. The consistently high quality and efficiency generates high-quality data, which, in the form of the standardised find graphics, are for the first time objectively comparable and do not require the experience of specialised technical draughtsmen.

With the development of TroveSketch, a simple and intuitive piece of software has been created through which traditional technical drawings can be replaced quickly, easily and with a high level of consistent display quality. With the excavation of the Neolithic well of Altscherbitz, efficient workflows were developed to salvage, clean and accurately digitalise large waterlogged organic finds in a near real-time manner. This experience was optimised within the EU-funded projects on medieval mining in the Erzgebirge, in order to make it possible to handle the find masses of several thousand pieces of wood that needed to be scanned. With their very high resolution, the structured light scanners have further developed possibilities of use in both archaeological and conservation contexts, e.g. with the detection of traces of wear and the monitoring of fragile and changing find classes.

The high-resolution 3D data, the 3D survey data and photos of the excavations are an integral part of the excavation documentation. This makes complex find situations and archaeological sites reproducible and comprehensible at any time and place. In particular, the results of the excavations, which were produced within the framework of ArchaeoMontan and the excavation of the Neolithic well at Altscherbitz, have digitally preserved the state of the site before its destruction for security reasons or before the block excavation was dismantled. As long as appropriate archives, sources and data are available, this can be scaled to almost any situation, i.e. to monuments or cultural sites that have been damaged or even destroyed by catastrophes. This shows the high value of digital archives enriched with high-quality data, which may be the only remaining source of information about damaged or even destroyed objects of any scale.

Modern web technologies, along with VR/AR applications, help communicate the information and understanding that has been acquired to the public and can provide considerable support to the transfer of knowledge. In reality, however, the originally high-resolution 3D models are usually far too large to be directly ported. Compressing and preparing the data (e.g. by map** new textures) creates a significant workload, if the visible quality losses are to be kept within limits. The same applies to researching archaeological data for the finds to be published.

The management of the raw data, and ultimately the readability of the proprietary measurement projects, represents a major challenge for the future. The measurement data of the 3D scanners from AICON, Artec and Konica Minolta differ completely in structure and format. To keep these data readable for as long as possible, suitable solutions and procedures must be developed, because the experience of the LfA Saxony shows that even after more than 10 years, new questions can lead to a demand for the raw data. Through the consistent use of open data formats (PLY, OBJ), LfA Saxony is in a position to process all 3D models from the last 15 years without any restrictions, as many of the models that can currently be seen on the institute’s Internet portal www.archaeo3d.de date back to the early years 2004/2005. The Internet portal represents an important step towards making the 3D data collected over the years and the research results obtained from them available to a broad public.