# The VIRTUALDiver Project. Making Greece's Underwater Cultural Heritage Accessible to the Public
## 3 Results and Discussion
### Santorini Case Study
World UI Canvas, a native Unity 3D tool, is used in order to place UI anywhere inside the 3D space. As the user interacts with the POI, he/she is transferred in the Walk Mode environment. Figure 14: Top View of Santorini with marked Points of Interest (POIs) (White mark: City of Fira, Yellow mark: User’s location, Red mark: Points of geological interest. 3D Model has been produced by Up2 metric VIRTUALDriver partners.) Figure 13: User interface of Map Route Chooser (screenshot): The user can choose between different routes through a map. In the Walk Mode (Figures 16 and 17), depending on the structure of the scenario, the user is either in a 3D environment or in the center of a 360\({}^{\circ}\) video. In this particular scenario, the user is inside a 360\({}^{\circ}\) video of the central square of Oia. The user stays stable while the video plays on a loop. Using the controls, different multimedia content can be retrieved by choosing the different Interaction Components located on the interaction bar, allowing the user to view additional information about the POI. Selecting an Interaction Component displays the corresponding UI, with which the user can interact. Figure 16: Walk Mode: Central square of Oia city—the Video Interaction Component is active. Figure 15: Fly Mode: User can navigate onto 3D terrain of Santorini, locate POIs and select them to enter Walk Mode. (3D Model has been produced by Up2 metric VIRTUALDriver partners)  
An additional choice is provided, on the interaction bar, for specially planned routes suggested by the VIRTUALDiver platform. This function provides a combination of POIs, based on their content, as well as a scheduled route for the user to visit (Figure 18). The user can easily navigate through those POIs and their Interaction Components without returning to the Fly Mode environment. The UI is designed in order to inform the user about the POI he/she is in at any specific time and provides indications of visited and not visited sites. By entering this mode, the interaction bar changes into a tour mode bar for easier navigation between the POIs. The user moves to the next section, in a three-dimensional environment, specifically to the city of Oia (Figure 19). There he/she has the opportunity to move around, process the environment, and be informed about the geological peculiarity of the area. The photorealistic model of the city of Oia is combined with a sea simulation system, a high-resolution Skybox, and ambient sounds. Figure 17: Guided tour by an expert—Green Screen 360\({}^{\circ}\) video production with a narrator (credits to [PERSON]). Figure 18: Specially planned route with the interaction bar changed into a tour mode bar. Navigation is achieved with VRTK's teleportation system, thus expanding the area in which the user can move without being limited by the physical space in which he/she is located. This also improves the user's sense of immersion, thus reducing the negative effects that can occur when driving in virtual environments, such as dizziness and nausea [54]. In order to move to the next section, the user interacts with a specially designed symbolic element and is transported in Diver Mode to an underwater environment (Figure 20). Here the user has the ability to navigate underwater, be informed about the flora and fauna, as well as interact with objects scattered on the bottom of the sea. Navigation in Diver Mode is similar to that in Fly Mode. The difference is that the speed is significantly reduced, compared to Fly Mode, to give a more realistic sense of underwater movement. In this environment, the user encounters fish and other marine species, which through artificial intelligence algorithms, move in space and around him/her. In addition, the user is able to choose which object he/she wants to interact with and gather more information about it, as well as hold and process specific three-dimensional objects, a function that increases realism and immersion. Figure 9:0 3D environment of City of Oia.