X3D Ontology for Querying 3D Models on the Semantic Web
Abstract. The Semantic Web offers significant capabilities that transform the current Web into a global knowledge base including various crosslinked multimedia content with formal descriptions of its semantics understandable to humans and processable by computers. Content on the Semantic Web can be subject to reasoning and queries with standardized languages, methods and tools, which opens new opportunities for collaborative creation, use and exploration of web repositories with reasoning and queries. However, these opportunities have not been exploited so far by the available 3D formats and modeling tools, which limits the presence of interactive 3D content as part of search and reuse on the Semantic Web. This work contributes a semantic development pipeline enabling creation of the X3D Ontology, with corresponding conversion of any X3D model into triple forms suitable for formal query. The ontology design reflects the experience accompanying the formal development of the Extensible 3D (X3D) Graphics International Standard, in particular, the X3D Unified Object Model (X3DUOM). This approach combines semantic and syntactic elements of X3D models and metadata to support integration with Semantic Web standards and tools. The demonstrated pipeline enables automatic generation of the X3D Ontology, thereby providing an up-to-date 3D representation with semantics during X3D specification development. By extending commonplace model conversions from other formats to X3D, the ontology further presents the potential to enable search for most forms of 3D content, which in turn can foster broad integration of 3D/VR/AR technologies with the Semantic Web.