3D models

Thanks to measurements of so-called photo-points made with the electronic tachometer the photographs taken from the kite could be rectified and used as so-called photo-maps, or raster for the master topographic map and geophysical survey. Calibration of the images was made basing on a series of control points (marked clearly on the ground in white colour) thanks to which the photographs were fitted for mapping purposes. After transformation the air photographs (photomaps) were subjected to a process of legibility improvement – vectoring the visible features of the landscape and archaeological features, complementing in this way site measurement data. In this manner were created 3D models of archaeological relics and fragments of site topography.

 The data from all the surveys and measurements was used as input to create a 3D visualisation of the site - DTM (Digital Terrain Model). Combining the elements of non-destructive studies makes possible not only the handling of maps or photographs but also databases containing information about the structures visible in the maps. In this way we obtained a tool for chronological and functional phasing. A numerical map which integrates data from different areas of research is a fundamental – non-destructive – instrument for the interpretation of urban archaeological sites. A map we can add to as new data is secured. Similar maps may be used directly to publish the results of research and are highly useful for making analyses of urban topography.

Under the same research project a provisional 3D reconstruction was made of the theatre at Akrai. Traditional methods of reconstruction (drawings, plans, models) make it possible as a rule to present only the general, artistic view of a building. 3D computer techniques make possible photo-realistic and high-precision presentation of a concept of a reconstruction of architecture informed by research. This is an important technical aspect of interpretation of archaeological and architectural evidence.
The theatre at Akrai reconstructed in our project had been investigated several decades ago and is documented only using traditional forms of recording – photographs and drawings. A 3D reconstruction is a combination of the latest digital technologies with traditional analogue documentation techniques. The theatre was created as a 3D database in the form of a geometric framework, to which were ascribed elements of two-dimensional documentation.

The plan of the reconstruction work was as follows: review and digitalisation of documentation from earlier excavation (plans, sections, photographs, publication of the building); validation, digital documentation using laser stations; generating a provisional 3D model containing all data available from archaeological research. As a next step, all data was subjected to architectural analysis, that is, integrated with input from other sources, written sources, iconography, analogies projects of similar date (e.g., theatres at Taormina and Syracuse). Basing on all this data three provisional 3D models of the theatre were created, presenting respectively: status of archaeological research, a status quo reconstruction of the theatre and a full reconstruction of the theatre in its form when it was in use.