The Semantic Web3d: Towards Comprehensive Representation of 3d Content on the Semantic Web One of the main obstacles for wide dissemination of immersive virtual and augmented reality environments on the Web is the lack of integration between 3D technologies and web technologies, which are increasingly focused on collaboration, annotation and semantics. This gap can be filled by combining VR and AR with the Semantic Web, which is a significant trend in the development of theWeb. The use of the Semantic Web may improve creation, representation, indexing, searching and processing of 3D web content by linking the content with formal and expressive descriptions of its meaning. Although several semantic approaches have been developed for 3D content, they are not explicitly linked to the available wellestablished 3D technologies, cover a limited set of 3D components and properties, and do not combine domainspecific and 3Dspecific semantics. In this paper, we present the main motivations, concepts and development of the Semantic Web3D approach. It enables semantic ontologybased representation of 3D content built upon the Extensible 3D (X3D) standard. The approach can integrate the Semantic Web with interactive 3D technologies within different domains, thereby serving as a step towards building the next generation of the Web that incorporates semantic 3D contents.

AnnotationBased Development of Explorable Immersive VRAR Environments Virtual and augmented reality environments consist of objects that typically interact with other objects and users, leading to evolution of 3D objects and scenes over time. In multiple VRAR applications in different domains, interactions and temporal properties of 3D content may be represented using general or domain knowledge, which makes them comprehensible to average users or domain experts without an expertise in IT. Logging interactions and their results can be especially useful in VRAR environments that are intended to monitor and gain knowledge about the system behavior as well as usersxe2x80x99 behavior and preferences. However, the available approaches to development of VRAR environments do not enable logging interactions in an explorable way. The main contribution of this paper is a method of developing explorable VRAR environments on the basis of existing environments developed using well established tools, such as game engines and imperative programming languages. In the approach, interactions can be represented with general or domain knowledge. The method is discussed in the context of an immersive car showroom, which enables acquisition of knowledge about customersxe2x80x99 interests and preferences for marketing and merchandising purposes.