Digital documentation and restoration tools reusing existing imagery: a multipurpose model of the Neptune’s Fountain in Bologna

On the occasion of the recent restoration of the sixteenth century Neptune’s Fountain in Bologna, promoted by the municipality in 2015 to preserve one of the major town’s landmark, high-quality imagery has been acquired for documenting the current state of preservation of the marble and bronze surfaces before and during the restoration phases. Starting from this available detailed photographic campaign and using new tools developed to solve problems linked with some limitations of the captured imagery, authors produced a photogrammetry-based 3D model of the monumental sculpture group, reliable for both geometric features and colour reproduction consistency, in order to be used to support the supplementary activities not foreseen in the original project. The paper presents methods and techniques implemented to produce the 3D model of the fountain, besides its main actual applications as a basic tool to support different restoration activities: (i) reliable documentation of the actual state; (ii) high-quality visualization and rendering; (iii) technical outcomes and graphical representation extraction; (iv) study of original and current water supply system and simulation of the new project for the jets system and watergames; (v) new lighting design simulation; (vi) structural analysis; (vii) support to preliminary analysis and design studies related to hardly accessible areas; (viii) surface cleaning analysis; (ix) base for filling gaps or missing elements through 3D printing; (x) support for data modelling and semanticbased diagrams.