## 3 Proposal of an Extended Reality Solution for Holistic Construction Safety Management
### General Description of the Proposed Framework
Firstly, this area considers the processes in the safety management of a construction project and the respective data and model packages associated with each of these processes. Different data and models will be incorporated into the processes associated with design development, construction planning, construction safety planning and safety monitoring and control. There will be BIM models of the project; safety analysis models; models and information associated with the terrain, construction elements and their planning; models and information on protection equipment, threats and accidents; along with work dynamics and information updates during project execution. The processes, models and data have been distributed within sub-zones according to the BIM dimensions, including BIM 3D (three-dimensional parametric models), BIM 4D/5D (schedule and costs) and BIM 8D (health and safety). All these elements will feed the XR environments. Although they are explained as inputs to the process, they enter into an iterative cycle. They will improve and will become more robust as a result of the different processes, cycles and iterations in the framework, receiving feedback and ultimately updating the project's design and management according to the safety perspective. * **XR programming, modelling and developments**. This area incorporates all the necessary aspects to develop the XR experiences, taking as inputs the models and data from the previous area. First, the data and models are reviewed to analyse whether elements need to be improved or optimised (e.g., BIM models may be too heavy to be supported in XR and/or contain more information than required, depending on the purpose of the XR implementation). Following this review, models should be improved and/or replaced for optimal use in XR (as the process matures in an organisation, optimisation should occur at the start of the project, and protocols  
Figure 6: Framework for an extended reality solution for holistic safety management in construction. should be implemented to facilitate this). So far, only BIM models and planning information are available (i.e., inputs for reconstructing XR scenarios; however, they are 'lifeless' scenarios). Therefore, new elements will be added to this information, focused on achieving interaction with the models and deploying the required actions and effects. Information will be added on construction site objects, workers in virtual or mixed environments (roles and bots), and aspects related to climate and other variables. For training, gamification and storytelling aspects will be required. All this will be integrated into XR development environments (usually, game development engines or specific commercial XR applications), including tasks associated with the physicalisation of models and environments; creation of people and interaction effects; effects for virtual scenarios, implementation of work dynamics and all required interactions; together with links to simulation models in different areas of interest. In parallel, according to the XR technology used, the developments will be packaged for subsequent interaction through glasses, computers and mobile devices, among others. * **XR interaction environment**. This area involves the deployment of safety management tasks from XR environments, through virtual, augmented or mixed reality. The technology will depend on the definitions of the project. In the early stages, virtual reality will be used more often, and will then be combined with mixed or augmented reality for deployment once the project is under construction or operation. The deployment involves the following tasks, with a focus on project safety: safety design and safety review; safety data and model preparation; protection system and PEE selection; safety planning and scheduling integration; safety planning review and safety training; operation and construction; and daily inspections and records.