Advanced 3D modeling versus Building Information Modeling: the case study of Palazzo Ettoreo in Sacile (Italy)

This paper presents an experience of 3D modeling starting from laser scanning data and following two alternative approaches: the first one, called “Advanced 3D modeling”, based on an original meshing algorithm, while the second make use of Revit BIM software. The case study in Palace Ettoreo in Sacile (Pordenone, Italy), constructed in Renaissance Venetian style in the 16th century: it has a trapezoid plan and is developed on three floors, with the ground one endowing a portico on two façades. The palace has been surveyed by two terrestrial laser scanners: a Riegl Z420i for 5 external scans and a FARO Photon 120 for 53 internal scans; also a topographic surveying of 270 targets have been carried out. The final TLS cloud has 1,4 billions of points. The Advanced 3D modeling has produced a “smart” mesh, allowing also to model the elements with deformations (out of plumb, bulges and troughs). Moreover, this model drastically reduce the stored data: the whole palace is modeled by 111.496 polygons only. The modeling with Revit follows the classical flowchart where the principal architectonical elements are gradually composed: this HBIM process has required a strong manual work in exploiting the available parametric objects and/or in the definition of new objects. Comparing the two models with respect the points cloud, both have evidenced advantages and limitations: therefore, the best solution is a process involving their combination. At the beginning, the Advanced 3D modeling is performed onto the points cloud, so well exploiting the segmentation tools and the smart meshing of the surfaces preserving any geometrical irregularity. Such obtained model allows metrical and morphological evaluation on the various structural and architectonical elements. Afterwards, this very light model becomes the entry data for the modeling in BIM environment, where also the shape of irregular elements are so imported.