Domes still represents a prickly subject, large dimensions coupled with a limited accessibility making their study difficult and time-consuming. Although throughout history this problem has been tackled in different ways, relevant methodological and operational issues have until now limited the success of these efforts. Digital technologies have radically changed this scenario. 3D active and passive capturing systems currently allow for a dense and accurate surveying while modelling software provides powerful tools to build virtual counterparts of surfaces and to investigate their geometric properties. The aim of this paper is to present three different projects developed by a research group in the Department of History, Representation and Restoration of Architecture—Sapienza University of Rome. Based on their results, the group has set up and tested a protocol that can guide users from acquisition through modelling and, finally, to the reading of the geometric properties of domes.

The paper aims at investigating modelling strategies in HBIM context to identify at what extent the final use of the model might affects, or should affect, the modelling approach itself. Moreover, the discussion wants to shed light on the possibility of connecting in just one digital environment several instances connected to the building. These aims will be discussed presenting and evaluating two different modelling approaches: the “black box” modelling and the “white box” model-ling. The two terms are partially borrowed from computer science to explain two types of testing. The “black box” testing is performed without any preliminary knowledge about the system functionality and internal components; on the contrary, the “white box” testing, implies a full knowledge of the system. These two approaches will be compared to two ways of conceiving a building information model. In conclusion, the paper will investigate the possibility to integrate in just one model, the grey box model, the two ones previously discussed.

BIM represents a significant step towards digitalization and innovation in the public construction sector in Italy, and as of 1 January 2025, its adoption became mandatory for all public work. Recognizing the importance of this shift, the Sapienza University of Rome developed a set of standards and guidelines between 2018 and 2024. These guidelines have now been officially adopted by the Buildings Maintenance Area of Sapienza for the application of BIM in service and work contracts. They are consolidated into a document known as the Sapienza Protocol, which serves as a reference for the creation of information-rich models of university heritage buildings, encompassing both existing structures and those to be constructed from scratch. The Sapienza Protocol outlines a modeling process that integrates surveying, geometric modeling, and an informational framework, combining theoretical principles with methodological approaches tested in the HBIM research domain. This approach ensures that both the technical and historical characteristics of buildings are appropriately represented. The purpose of this manuscript is to describe the evolution of the Sapienza Protocol, from its initial version to its current form. It highlights operational procedures and technical solutions, showcasing how the protocol has adapted to address the complex needs of managing and preserving architectural heritage in a digital context.