Augmented reality (AR) still struggles to be widely used in real processes in the construction industry despite its great potential. This is partly due to the difficulties that exist in aligning holograms and maintaining their stability, especially for outdoor applications. In addition, being indoor-outdoor interactions crucial for built environment management, it would be important that AR apps can work seamlessly. Alignment in indoor environments cannot make use of methods such as GNSS, nor can all environments be assumed to have been previously initialized with AR tools. Thus, marker-less AR registration is crucial for indoor applications. This paper presents an approach for marker-less AR registration seamlessly in both outdoor and indoor environments. Real-time kinematic positioning (RTK) and Inertial Measurement Units (IMU) technologies have been chosen for outdoor registration, while image comparison based on convolutional neural networks (CNN) for indoor registration. In this research, the application of these two technologies and their integration have been studied and tested on site on a real Facility Management use case related to a university campus. The proposed approach has shown very promising results in displaying BIM elements of the electrical system seamlessly superimposed through AR to their physical counterparts in mixed indoor-outdoor environments

Safety management in construction sites has always been one of the most sensitive aspects of the AECO industry and a problematic that recalls the complexity of such a multifactor domain. The high number of work accidents that occur on construction sites is also caused by the fact that not all the information to work safely is always available. For instance, visibility during some maneuvers is a key aspect of safety in operations, and this is often impeded due to the layout of the construction site and working methods, especially in the use of some equipment. The latest approaches in order to overcome complex situations is represented by the Digital Twin paradigm. This approach has among its main criticisms:1) the way of connecting physical reality and its digital replica and 2) the system for exploiting the combination of real-time data and digital applied intelligence for supporting operations on site. This paper proposes a framework for the development of digital twin of the construction site. An application of augmented reality that exploits the concept of diminished reality and workers location detection will improve visibility during critical operations

The management of the built environment is a topic that requires reference to the management of complex systems. In fact, the variety of domains involved means that the management of urban centers is not only complicated, and therefore it is not enough to model a set of rules that are representative of phenomena related to the real environment. Not only that, but what is evident is that emergency management lacks the ability to access real-time information that could be decisive. Having tools that provide real-time data, that reprocess it, and that are able to provide an enriched and slightly predictive view of what is happening offers the possibility of having a real impact in the management of the built environment. In this sense, digital twins are a valuable approach to achieving the desired results. Digital twins through the integration of technologies such as lnternet of Things (IoT), simulators, Artificial Intelligence (AI), and Augmented Reality (AR) technologies make it possible to develop systems capable of exploiting the concept of collective intelligence, in a digital version, through a large number of heterogeneous agents working according to stigmergic mechanisms. This research work aims to propose its own architecture of digital twins for the management of resilient urban centers, with particular reference to the management of post-earthquake reconstruction scenarios