ARPattern Prefabs (for Interaction Design Patterns)

What are ARPattern Prefabs?

ARPattern Prefabs are a collection of so-called prefabs made available in Unity. According to Unity tutorials (https://learn.unity.com/), a prefab is “a special type of component that allows fully configured GameObjects to be saved in the project for reuse”. LoGaCulture’s ARPattern Prefabs is actually a set of interactive design pattern components developed using the Unity3D engine, specifically designed to support head-mounted augmented reality (AR) devices such as the HoloLens 2 and other AR-ready devices. As an enhancement to existing Unity technologies, it aims to assist AR experience creators in rapidly implementing typical interaction patterns that have been researched as being relevant to visits of museums and CH sites with AR. The collection of design patterns is described elsewhere from the perspective of design, while the ARPattern Prefabs codify this design knowledge in executable, prefabricated software components. These incorporate parameter sets for interaction design with pre-tested default values so that developers can efficiently make modifications, perform rapid interaction tests and thus be supported in the final implementation. Simply adjusting parameters in the Unity Inspector window reduces the need for additional coding or redevelopment.

Example ARPattern Prefab: Forward Cue Path Routing

In the following, one particular interaction pattern is taken as an example (Figures 1 and 2), which is designed to guide users toward specific points of interest (POIs) in a museum. It employs a visual interface that successively displays circular shapes to direct visitors along a gradually evolving predefined path. 

Figure 1: Example: The prefab for the interaction design pattern of “Forward Cue Path Routing”, as shown in the Unity interface for authors.

Specific customisation steps (see Figure 2):

• Customising the spawning behaviour of circles: Authors can adjust parameters such as the generation speed and width of the circle pattern interface in the “customising the spawning behaviour of circles” section.
• Customising the appearance of a single circle: In the “customising the appearance of one circle” section, AR developers can modify attributes such as the size, position, and colour of individual circles.
• Event after Last Node Reached: Authors can quickly add or connect further event triggers while the guiding interaction
• Pre-Test buttons (below): Allow developers to quickly test the guiding functionality in the Unity runtime environment, facilitating an efficient evaluation of a stub of the final experience, without having to travel to the location.

Figure 2: Authoring and customisation functions of the Forward Cue Path Routing prefab based on circular shapes.

ARPattern Prefabs in LoGaCulture

The LoGaCulture project is testing how the development of AR Pattern Prefabs supports the rapid creation of effective interaction patterns that are specifically tailored to public participation in physical exhibitions, such as in museums, and which can be executed on immersive AR devices such as HMDs. For instance, the “Forward Cue Path Routing” pattern with circular shapes (Figure 3) allows the audience to navigate from step to step while feeling present in the physical space, and guides their attention through rich museum exhibitions that are combined with immersive digital artistic overlays. 

For the creation of these immersive AR experiences, the prefab toolset enhances usability while enabling swift testing, validation, and evaluation of timely AR experiences. Through the reuse and combination of prefabricated components, content creators gain greater creative flexibility, promoting the widespread application of AR technology in the cultural heritage sector. The modular design of the ARPattern Prefabs reduces the barrier to content creation, fosters interdisciplinary collaboration, and offers greater flexibility for personalised content customisation.

Figure 3: Experience of being guided through forward cue path routing with circular “cue” elements, watched through a HoloLens 2 at the Senckenberg Nature Museum.