Today, the practice of making digital replicas of artworks and restoring and recontextualizing them within artificial simulations is widespread in the virtual heritage domain. Virtual reconstructions have achieved results of great realistic and aesthetic impact. Alongside the practice, a growing methodological awareness has developed of the extent to which, and how, it is permissible to virtually operate in the field of restoration, avoid a false sense of reality, and preserve the reliability of the original content. However, there is not yet a full sharing of meanings in virtual restoration and reconstruction domains. Therefore, this article aims to clarify and define concepts, functions, fields of application, and methodologies. The goal of virtual heritage is not only producing digital replicas. In the absence of materiality, what emerges as a fundamental value are the interaction processes, the semantic values that can be attributed to the model itself. The cognitive process originates from this interaction. The theoretical discussion is supported by exemplar case studies carried out by the authors over almost twenty years. Finally, the concepts of uniqueness and authenticity need to be again pondered in light of the digital era. Indeed, real and virtual should be considered as a continuum, as they exchange information favoring new processes of interaction and critical thinking.

The web and its recent advancements represent a great opportunity to build universal, rich, multi-user and immersive Web3D/WebXR applications targeting Cultural Heritage field—including 3D presenters, inspection tools, applied VR games, collaborative teaching tools and much more. Such opportunity although, introduces additional challenges besides common issues and limitations typically encountered in this context. The “ideal” Web3D application should be able to reach every device, automatically adapting its interface, rendering and interaction models—resulting in a single, liquid product that can be consumed on mobile devices, PCs, Museum kiosks and immersive AR/VR devices, without any installation required for final users. The open-source ATON framework is the result of research and development activities carried out during the last 5 years through national and international projects: it is designed around modern and robust web standards, open specifications and large open-source ecosystems. This paper describes the framework architecture and its components, assessed and validated through different case studies. ATON offers institutions, researchers, professionals a scalable, flexible and modular solution to craft and deploy liquid web-applications, providing novel and advanced features targeting Cultural Heritage field in terms of 3D presentation, annotation, immersive interaction and real-time collaboration.

This article is framed into the theoretical and methodological background of virtual archaeology. The advantages of virtual archaeology and its weak points have long been discussed in academia, formulating theoretical foundations and principles to be followed in order to guarantee scientific results, where data are traceable, transparent and verifiable. Gathering the inheritance of the last 30 years of debates and research, this work proposes implementing these principles through the formulation of a methodological approach, to virtual reconstruction of archaeological contexts, consisting of an application protocol articulated in five steps. In particular, the proposed methodology is grounded in the Extended Matrix (EM), a formal language and tools entirely developed and tested by the Virtual Heritage lab of the CNR ISPC. The EM takes its cue from the Matrix of Harris and adapts its system to the specific needs arising in the fields of virtual reconstruction and scientific visualisation. This protocol, which ranges from fieldwork to the publication of scientific data, has been tested and systematised in over ten years of activity on various complex and significant archaeological contexts. In the article, each methodological step is supported by case studies described in detail and accompanied by a graphic apparatus that clearly illustrates the results obtained. These case studies led to the definition of version 1.2 of the EM as described in the methods section.