The dissemination of the tangible and intangible values of heritage building represents one of the most important objectives in the field of Digital Cultural Heritage (DCH). In recent years, different studies and research applied to heritage monuments have shown how it is possible to improve the awareness of the architectural heritage through the integration of latest developments in the field of 3D survey, 3D modelling, Building Information Modeling (BIM) and eXtended Reality (XR). On the other hand, this digital workflow requires a huge amount of data sources and a holistic approach to reach a high level of information sharing coming from different disciplines and sectors such as restoration, geomatics, 3D virtual museums and serious gaming. In conjunction with entertainment software and gaming, this research shows the main results obtained during the generative process of digital environments oriented to improve the level of information and to enrich the contents coming from the informative models. The case study is represented by one of the most important Lombard monuments: the Basilica of Sant’Ambrogio in Milan. This study, starting from the 3D survey and the data collection of the historical records of the church, improves the creation of an XR experience that reaches a new level of interactivity for different types of devices (desktop, mobile, VR headset) and users (experts, non-experts).Highlights:Generative modelling requirements and novel grades of generations (GOG) and accuracy (GOA) are presented in order to improve the digitisation of built heritage from the 3D survey, reducing time and costs of the scan-to-BIM process.The holistic value of generative modelling allows experts to create digital worlds able to faithfully and accurately represent the detected reality and improve new immersive environments for Virtual Reality (VR) and Augmented Reality (AR) projects.Immersive environments are created with a mixture of the latest generation software and hardware, allowing users to discover the hidden historical values of built heritage with new levels of interactivity and information.

The HBIM of the Basilica di Collemaggio in L'Aquila is part of the restoration project of the building seriously damaged by the earthquake in 2009. The project "Ripartire da Collemaggio", funded by ENIservizi, involves an interdisciplinary group called to work together toward a common goal: the need of security of the structures and the need of conservation of the architectonic value of the Basilica. Starting from the photogrammetric and laser scanning survey, interpretation and modelling were needed to create a detailed HBIM to manage the phases of analysis, simulation of structural behavior, economic evaluation of the project, and final restoration. This paper described the generation of the HBIM and its use in the on-going restoration project with a particular attention to the procedures used to preserve the complexity given by photogrammetric and laser scanning data.

Today, a building is not just a “body” or a “machine” as defined by modern architecture, but rather an immaterial entity immersed in a digital world where not only its components but also the information associated with it are accounted for. In recent decades, building information modelling (BIM) has made it possible to move from 2D CAD drawings to 3D models capable of supporting different processes and interacting with different disciplines in the AEC industry for storing, documenting and sharing heterogeneous content. It has thus become possible to direct these techniques towards built heritage to investigate new forms of communication and share heritage building information modelling (HBIM) models. This research investigates this evolution in both generative terms (scan-to-BIM process) and cultural and historical terms in order to orient BIM uses towards novel forms of interactivity and immersion between users and models. The author proposes the use of a digital process and the development of VR and AR environments based on a visual programming language (VPL) to improve access to a deeper knowledge of HBIM models and the artefacts and information contained therein.