Marking the City: Interactions in Multiple Space Scales in Virtual Reality This article shows an overview of an immersive VR application to explore, to analyze and to mark largescale photogrammetric 3D models. The objective is to interrogate the effectiveness of the proposed navigation process and annotation tools for spatial understanding. Due to the amount of interactions, different kinds of menus were necessary: desktop coordination menu, radial menu attached to the controller and 3D spatial menu for creating markers. Besides the menus, the navigation tasks through different perception space scales required a great number of interactions metaphors, patterns and techniques displaying the complexity of the user experience in Virtual Reality for understanding and analyzing urban digital twins. Those interactions allowed by the user interface were then analysed and classifyed according to a theoretical background and were experimented in preliminary tests with end users. Although designed for particular needs of the army, the tools and interactions can be adapted for city models explorations and urban planning. For future steps of the research, a usability study is going to be performed to test the performance of the interface and to have more end users feedback.

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.