An ontology for 3D cultural objects

3D cultural objects are digital 3D replicas of objects having a cultural value, as models of artefacts, reconstructions of buildings, sites and landscapes. As such, they have a twofold nature, and inherit properties both from their digital nature, like the shape and texture, and from the cultural content, for instance to be used for scholarly purposes or communication to the public. In some cases, one of the natures prevails on the other. This may be the case because the object is being processed, e.g. visualized on a computer, or scrutinized by heritage scholars for review. In a few others, it is unfortunately the user's narrow-minded attitude that leads to take into account only one nature of such an object and neglect the other. It is therefore necessary to explore a way of documenting 3D cultural objects that keeps together all the relevant information, both the cultural and the digital one. In this paper we propose an ontology for such complex objects that owns the following important properties: i) it is sufficiently general to encompass very different artefacts, from pottery sherds to historical landscapes; ii) it fully complies with international standards for heritage, in this case CIDOC-CRM, of which it can be shown to be a specialization/ extension; iii) it is sufficiently simple to be used and understood by heritage practitioners and professionals with moderate computer skills, and documents items in a plain, human readable and understandable way; iv) items documented as instances of this ontology can be efficiently processed for the most frequent purposes, as computer visualization, retrieval of cultural information or storage in a database; v) it is ready for compliance with other important requirements, as for instance the proposed charter on credibility known as London Charter.