Status and Progress of the Project 2006
After a brief preparation period the project started in January 2006. Since then, the archaeologists and architects of the team have been working in their particular fields, partly together in the catacomb for field studies, partly separately in the individual institutes for the analysis of the results. In the beginning the work was entirely geared towards the first goal of the project: the compilation of the repertory of paintings of the Domitilla-catacomb.
Focal point of the work in the catacomb was the documentation with the 3D-laserscanner. Three scanning campaigns were carried out in 2006. The first campaign in January was of experimental nature and served to coordinate the modus operandi and the work sequence while scanning in the catacombs. A series of individual projects of standard situations was generated, of which some shall be shown:
The scanner orientates itself on temporarily applied reflector points (Fig.1). In 360-degree panorama-scans it generates so-called point clouds, which reproduce the surrounding area of about 1 m distance as a 3D-structure. In order to connect several scans with each other, further scan positions with at least five already known reflector points are selected. At the same time as the scan, a digital camera mounted on the scanner produces photo data that can directly be applied onto the point cloud. The advantage of this method lies in the mobility of these point clouds, which can be viewed from the outside as well as the inside and which can be virtually entered. Depending on the projection and position, a ground plan, cross- and longitudinal sections and 3D views are retrievable.
As an example of a small tomb with painting, the cubiculum of Veneranda in the Retrosanctos area behind the basilica was chosen (Fig. 2). The nine scan positions that were necessary for the complete documentation of the entire chamber are shown in the illustration. On the back wall the photo data of the painting in the arch of the arcosole is already applied; one can see the portrayal of the deceased Veneranda, who is lead into a paradise garden by Santa Petronilla.
The scans made of a group of chambers in a gallery in the Retrosanctos area were coloured after their allocation to specific tombs (Fig. 3). One can clearly see the light-wells that are closed off on top today (Fig. 4).
The situation in the Galleria dei Flavi, formerly an adit constructed with niches for burials with sarcophagi, which is completely painted, is especially complex (Fig. 5). The combination of architecture and painting impressively emerges by applying only a single photo onto the point cloud (Fig. 6).
Finally, the view of the entire region of the basilica and the Retrosanctos that was scanned in the first campaign gives a good impression of the potential of the 3D-laserscanning method. Furthermore, it allows movements and continuous view changes from the ground floor perspective (Fig.7) into side views (Fig. 8) on the computer.
A second focal point was the work on the compilation of photorealistic 3D-models of singular chambers that are endowed with painting. These models are an important enhancement for the repertory of paintings in comparison with the so far prevailing black-and-white drawings.
In the beginning the archaeological research concentrated on the paintings as well. Next to the work on the extensive bibliography for every single painting, the systematic stock-taking in the monument itself was the main focus in 2006. Several paintings were newly discovered and interpreted. The large amount of new material broadened our knowledge considerably, for example on the painting style of entrances and on new scenes in the repertoire of Christian images. They offer new approaches for interpretation and not least important information for the chronological classification of individual areas of the catacomb. The presentation of this new material is underway (see literature list).