Natural Interaction in VR environments for Cultural Heritage: the virtual reconstruction of the Regolini Galassi Tomb in Cerveteri

The final aim of a virtual elaboration is to multiply the communicative potentialities of cultural heritage, re-activating its relations in space and time and meanings. Virtual reconstructions, in fact, can illustrate what is illegible, contextualize what is fragmented or isolated, and put back together cultural ties that have been separated over time and which are essential to reconstruct the cultural identity of the object. These aspects are seldom brought to the at- tention of the public in traditional approaches to cultural transmission. "Virtual Heritage" is information that cultural heritage represents and this information modifies its value, interpretation and possibility of transmission, producing an interchange between the cultural content and the public. Despite this great poten- tial, however, virtual museums often lack communicative and emotional impact, probably because there is still not enough collaboration between industry and research, that develops tools dedicating little interest to their wide application. Moreover there is the misconception that cultural heritage is self-explanatory in terms of aesthetics and conceptual value and consequently little attention to communication is necessary. On the contrary every cultural object conveys a message that needs to be "decoded" and transmitted to the public and this transmission is not easy for several reasons (Antinucci 2004). At the origin of the "digital cultural heritage era" the main goal of research was to obtain good digitization of monuments and archaeological sites, topographically and topologically reliable and accurately measured. Advances in the development of new technologies led to the improvement of many more instruments, the integration among technologies and meth- odologies, thereby achieving better digital pipelines to preserve the original quality of the data, from its acquisition and documentation at high resolution to the final 3D representation (Pietroni, Pescarin 2008). At the same time, geographic information systems have increased their potential in terms of features: data dispersed in multiple archives and in a variety of formats can now be brought together and organized in a unique and coherent 2D or 3D context, with great potentialities of analyses (Pietroni 2009). Bottom up and top down approaches have been integrated to show the 3D representation of an artifact in its actual state of preservation and furthermore, how it could have been in the past, through a virtual reconstruction based on historical sources and interpretative work. The London Charter, the Sevilla Principles and a widespread debate on an international level have focused attention on the need to make the whole methodology and the interpretative process ex- plicit, to create repositories where data can be shared and meta-data opened to verification, criticism and possible re-use by the body of the users. Basi- cally, still today, the scientific value of digital cultural transmission has been identified in these kinds of activities and development focusing especially on digital documentation and preservation. Despite advances made in this field, most of the digital applications utilized in museums for communication purposes are still lacking in terms of real impact on the public. They still ap- pear as "experiments" born inside laboratories and their target is not always evident. As learning faculties are deeply influenced by emotional involvement, also other aspects, connected more to the artistic impact and the interaction design, must be taken into account, if virtual museums are to satisfy the needs of a wider public audience. Reliable and accurate 3D models and digital archives need to be considered as fundamental but initial steps towards final cultural transmission. Efforts should not be limited to the formal aspects of cultural heritage and to the analytic organization of knowledge, following criteria oriented to classification and taxonomy. Attention should be centred on the thematic and anthropological contents, as the final purpose. No gap should exist between knowledge and communication; there is no context without communication and there is no communication without a context (Bateson 1979). If we want to definitively transmit to the public stories that are helpful in enhancing the cultural ties of an object, it is clear that we need to focus more on narrative plots, non-linear and interactive storytelling, interaction interfaces, gaming rules applied to CH, user profiling methods and "soundscapes". How these items interrelate with each other should be taken into consideration: criteria and best practices can change according to the final output and the conditions of use. In this perspective cognitive science and art are as fundamental as the other, more consolidated, disciplines; a stronger collaboration between science, art and technology, museums and researchers is doubtlessly recommendable. One of the critical aspects is that visitors to museums still have prob- lems managing common input devices (mouse, joystick, keyboard, console) for interacting in a VR environment. This condition produces uneasiness and frustration in establishing a contact between the visitor, the digital environ- ment and technologies. Moreover, the users are sometimes discouraged by the absolute lack of information linked to a virtual representation or, on the contrary, by an excessive amount of information that is confusing or mislead- ing. It is extremely important to fnd a good compromise between freedom of exploration, easy use of the interfaces and the possibility of guiding the public through the learning process. Natural interaction in VR environments for cultural heritage: the virtual reconstruction In the next paragraphs reference will be made to the Etruscaning 3D project where research is oriented to the development and experimentation of new, low cost and markless natural interaction interfaces in a VR environ- ment in museums, based only on body movements. This solution makes interaction extremely easy and natural for the public, consequently resulting in a longer time of use, more pleasure and a better impact in terms of learning. The choice of natural interaction is not a purely technical solution for input. It strongly influences the user's experience, the perceptive impact of real time exploration, embodiment (the real user and the digital world are in effect in the same space) and sensorial participation, object selection, manipulation interface, the combination of media, the dura- tion of the narrative content and motivation to continue the experience.