The research here proposed concerns the documentation of cultural heritage through interconnected methodologies focused on architectural survey, historical understanding and restoration to create 2D and 3D models. The aim of the study is to understand at what extent the ‘digital twin’ of the object can be used as a common base for heterogeneous analysis. Furthermore, the paper aims to discuss proportional and geometric considerations related to the use of architectural order in the designing process of the first decades of the XX century. The case study is Palazzo de Gaetani in Genua (Italy). The building is thought on the style of Palazzo Koch in Rome, completed a few years earlier, with which it shares two characteristics: firstly it shares the name of the architect who designed it, Luigi De Gaetani for Genova and Gaetano Koch for Rome; secondly both are characterized by stylistic features that can be traced back to the ancient architectural language. The building is organized by a first register marked by arches with bugnato; and a upper register is marked by aedicule windows with tympanums. The data elaboration phase focused on two complementary goals. The first one was to product specialistic 2D and 3D models to support each specialistic analysis; the second result concerned the fusion of different models into a unique information system. This study sheds light on new ways of thinking integrated research and new strategies to support knowledge through digital models.