An open source application for interactive exploration of cultural heritage 3D models on the web

In recent years, the integration between laser scanning technology and photogrammetry has been proven to be a very effective methodology to provide high-resolution 3D models of heritage sites and cultural artifacts. Furthermore, the availability for faster connections to the Internet and for more performing servers and browsers have pushed the development of interesting web-based Virtual Reality applications. Several works published so far have demonstrated how Cultural Heritage (CH) can greatly benefit from 3D modelling and Virtual Reality applied to object or historical/archaeological site analysis, documentation, preservation and restoration. Virtual Reality environments created for these purposes represent very often an easy way to give accessibility to CH among a wide variety of users. However, these tools provide only limited knowledge about the element of interest which is represented, mainly geometric, color and texture characteristics of the object as it existed at time of survey: historical and artistical details are often omitted. In this paper we present the development of a WebGis-based application which allows the user to interactively explore Cultural Heritage 3D models, integrating geometrical and non-geometrical information. While walking through the virtual reconstruction, the user can get information about historical, artistic and architectural aspects, which are usually found on the tour guides or specific books. The main aim of this interactive system is to provide the user with a completely new visit experience based on a free interactive exploration of the object (i. e. not constrained by any predefined pathway) and on the opportunity to get more detailed information on parts of interest in the form of papers, photos and videos, widening therefore his/her knowledge with respect to a simple and classical walk through. The developed application is based on open source tools, thus providing full transparency on adopted methodology and on used data. The information system, based on a completely thin-client architecture, is a WebGIS platform seamlessy integrated with a Postgres DBMS and X3D file format for data representation. The architecture uses PHP and Mapscript/Mapserver for scripting, while Blender is adopted for model editing and format conversion between VRML2 and X3D.