Model and experience. Measuring deformations of rupestrian architectures in the area of Goreme

The tufa limestone that characterizes much of Cappadocia is a sensitive material to be shaped both by wind erosion and by man’s tools. For centuries these parallel actions have been producing a highly dynamic landscape, which changes in real time and in which what is artificial is hardly distinguishable from what is properly natural. The rock habitats has often developed from pre-existing natural caves but certain architectures created by subtraction demonstrate precise spatial and stylistic intentions. Rock-cut monasteries and churches often reference to models consisting of the traditional Byzantine architectures and attribute a supplementary semantic role to decorations and paintings. Obviously, the constructive precision of these architectures is caused by both specific historical events and inconstant technical skills of the builders. Nevertheless, most of these "full-scale models" were usually perceived and registered in XX century surveys (Jerphanion, Rodley, Thierry) as rather regular structures. The surveys conducted with automatic photogrammetry in recent years have however revealed that the form of most of the rock-cut rooms is often very irregular. As part of a national research, the authors have participated in the survey and the digital documentation of some monumental sites in Goreme, using primarily laser-scanner and numeric models to produce faithful and incorruptible models of a number of sites. A further possible application of these models is to relate the true shape of the rooms with the way people perceive and experience them. This paper presents the results of a study on the interior geometries in order to define the range of such deformations compared to supposed regular, symmetrical and basically orthogonal models behind them, in order to measure the threshold of their actual perception. Even if the sensitiveness to space is largely a cultural inconstant phenomenon, as a corollary, this paper could contribute to understanding some of the intents of their builders between reproduction of models and original research.