TransferAR

Why TransferAR?

AR experiences in Cultural Heritage contexts are often location-based, which means they are linked to specific geographical locations, rooms or exhibits. This locative aspect makes it difficult to transfer AR experiences to other exhibitions. Variations in spatial layouts, lighting conditions, and audience demographics necessitate that location-based AR experiences be tailored to match the specific context of each museum.

Given that many museums display similar types of exhibits depending on their focus — such as whale skeletons, dinosaur fossils, and mammal displays in natural history museums — there exists a great opportunity for reusing and adapting existing AR experiences. Such reuse could mitigate development effort and costs, especially for complex immersive HMD-based applications. Further, in the collaborative project LoGaCulture, transferring AR experiences between associated museums can enhance shared research.

What is TransferAR?

TransferAR is an authoring environment that supports the transfer from pre-made AR experiences for museums and CH sites to other exhibitions by customising them accordingly. It works as an extension for Unity, therefore authors need to possess a basic understanding of how Unity functions. They do not require in-depth coding knowledge. We chose Unity because of its popularity and its robust community, which supports the creation of AR experiences.

This extension offers several advantages over plain Unity to enhance the authoring process. It reduces the amount of coding required through a user-friendly drag-and-drop mechanic. The setup of an AR experience is divided into the three parts of 1) location-sensitive assets, 2) logic and 3) presentation to implement a flexible structure that allows for changes in one part without touching another. The logic of the experience is broken down into so-called blocks that represent coherent micro-experiences. For example, two neighbouring exhibits could feature AR content. Each exhibit would be represented in one block, depending on the type of AR content. Currently, TransferAR allows for sequential explanation (visual and audio guide), conditional experiences such as mini games, and integrating customised and self-programmed mini-experiences. The prototype enables authors to selectively retain the logic, presentation, and/or assets of an existing AR experience during the adaptation process. It provides easy access to the components that require redesign or re-implementation, allowing other parts that can remain unchanged to stay intact.

How to use TransferAR?

A TransferAR user can start with a scene in which an AR experience is already set up with the tools of the extension. For customisation and adaptation, authors have multiple options. Most importantly, since the new exhibition will almost certainly have a different layout, they can exchange site-specific content in the hierarchy. Placing locative content in the scene works as usual in Unity, such as simply adding 3D objects, animations, sound and other location-bound assets to the hierarchy. The only requirement is to place them beneath the AnchorPrefab Parent, so that during runtime on the end device, the location of the objects in the real world can be saved.

If the existing locative content assets can be re-used, authors can also add their own logic blocks where they can quickly prototype mini-experiences by drag-and-dropping the existing assets into the inspector of the newly created block (Fig. 2). Different types of logic blocks can be added by right clicking in the hierarchy. Currently, sequential explanation, condition and custom are supported. A block then shows up in the hierarchy (see Fig. 1).

Figure 1: Hierarchy in Unity showing the division between locative content, logic and UI.

For each block, there is a number of settings the author can change (Fig. 2). The author can specify if a block is available at runtime, whether it is replayable after it has been completed once, if it is ready to be played by a user on application start (“Ready on Start”) or whether it should already be running when the application is started (“Active On Start”).

Aside from that, there are so-called conditions that define when a block is ready to be played, how a user can activate it and how a user can exit it. There is a set of pre-defined condition types such as collision with a 3D object, distance to a 3D object, as well as checking variables such as booleans that change value after another part of the overall experience is completed or fails.

Figure 2: Example logic block featuring the Orca skeleton exhibit in the Senckenberg Museum.

Example

Using TransferAR, a labeling game addressing the homology between humans and vertebrate animals has been transferred between exhibits. Starting with a human mannequin as example exhibit, players can match virtual human bones with the physical mannequin (Fig. 3). In addition, they can place the Latin names of the bones, together finding the correct match of bone and Latin name. We transferred this game to the natural history museum in Funchal, Madeira (Fig. 4) and to the Hessisches Landesmuseum in Darmstadt, Germany (Fig. 5).

Figure 3: Labelling game using a human mannequin.

Figure 4: Adaptation of the labeling game to a seal skeleton in the Natural History museum in Funchal, Madeira.

Figure 5: Adaptation of the labelling game to a hoofed animal in the natural history department of Hessisches Landesmuseum in Darmstadt, Germany.

The TransferAR Team is:

Jessica L. Bitter – Researcher, AR Developer and Designer
Dr. Ulrike Spierling – Principal Investigator