Because we cannot expect every user of a museum installation to be experienced with computers, developing an intuitive and easy to use navigation interface is important to enable all visitors to use our system.

Free Navigation

While the visitor should be able to freely explore the ancient city, he/she shouldn’t be allowed to go to parts of the scene, which are not relevant, or rotate his viewpoint about any angle in 3D-space.Any of these two cases would quickly leave the user lost in hyperspace. Furthermore collision detection has to be used to avoid users passing through objects. We use a terrain following map to solve all these issues in an efficient way.

Navigation and Interaction Device

Not all users accept keyboard and computer mouse as an ideal user-interface for navigation. We developed a novel device by mounting a simple cardboard “display” with a back-projection foil as screen on top of a spacemouse. A projector is used to project the image onto the foil from behind. By means of turning and pushing the display the user can navigate through the scene or manipulate objects.

Guided Tours
To avoid the feeling of getting lost, free navigation is complemented with predefined camera animations, where the visitor can take virtual tours through the site.
On the upper agora we use signposts the user can select to start a tour to the most important “sights”. On the lower agora, we use an avatar as a virtual guide instead.

Guided tours through signposts (left) and virtual guide (right)

Since no serious museum would present its exhibits uncommented to the public, just displaying a 3d-reconstructed scene is not enough. Therefore we aim to integrate various kinds of interactive multimedia content, to add educational value without disturbing the appearance of the visualisation.

Integration of text, images, and recorded objects in the virtual environment (from left)

The following media can be integrated:

· Textual Information – Explaining text for artefacts can be displayed at any time.

· Images and Movies – Pictures of a real find can be compared with its reconstruction; movies taken from the excavation can be blended into the virtual environment.

· Sound – Background-sounds and speech can be integrated into the scene.

· Recorded objects
The user is able to select recorded objects directly on their place, where they might have been in the ancient city. He/she can zoom in and rotate the object interactively, to get a 360-degree view of the find.
Thus, it gets immediately clear, what purpose a certain find had in former times and in what environment it has been used.

· Panoramic Images
A 360-degree panorama taken from the actual site can be smoothly faded with the reconstructed 3d-scene. By being able to control the transparency of the panorama overlay the user can compare reality with hypothesis in a very intuitive way.