Survey of 3D digital heritage repositories and platforms

Despite the increasing number of three-dimensional (3D) model portals and online repositories catering for digital heritage scholars, students and interested members of the general public, there are very few recent academic publications that offer a critical analysis when reviewing the relative potential of these portals and online repositories. Solid reviews of the features and functions they offer are insufficient; there is also a lack of explanations as to how these assets and their related functionality can further the digital heritage (and virtual heritage) field, and help in the preservation, maintenance, and promotion of real-world 3D heritage sites and assets. What features do they offer? How could their feature list better cater for the needs of the GLAM (galleries, libraries, archives and museums) sector? This article's priority is to examine the useful features of 8 institutional and 11 commercial repositories designed specifically to host 3D digital models. The available features of their associated 3D viewers, where applicable, are also analysed, connecting recommendations for future-proofing with the need to address current gaps and weaknesses in the scholarly field of 3D digital heritage. Many projects do not address the requirements stipulated by charters, such as access, reusability, and preservation. The lack of preservation strategies and examples highlights the oxymoronic nature of virtual heritage (oxymoronic in the sense that the virtual heritage projects themselves are seldom preserved). To study these concerns, six criteria for gauging the usefulness of the 3D repositories to host 3D digital models and related digital assets are suggested. The authors also provide 13 features that would be useful additions for their 3D viewers.