Brandon Vassion
Masters of Science Thesis Project, May 2023
[Proposal Thesis Presentation]
Augmented Reality (AR) studies the approaches that enhance reality by integrating virtual content into the physical environment in real-time. In the simplest form, virtual objects in the physical environment are stationary, where AR applications serve as powerful tools for visualization. The support of interaction with objects in the environment brings the AR application from being passive for observing the augmented world to one where the user can actively explore. When the interactions follow intuitive physical world constraints, an AR application, or constraint-based AR, can immerse users in a realistic augmented world.
We categorize 
existing constraint-based AR by the relationship between and interaction of the objects being constrained: virtual objects constrained by virtual objects, physical by virtual, and virtual by physical. This straightforward classification provides insights into the types of and potentials for useful applications. For example, virtual by virtual can describe the pages of a virtual book being constrained where the corresponding interaction would be the flipping of the virtual pages. In contrast, physical by virtual would mean placing a physical coffee cup over the virtual book. Lastly, virtual by physical would be placing and pushing the virtual book on an actual physical desktop. The subtle and yet crucial differences are that in the first case, the objects and the interactions can also be carried out in a pure virtual 3D world, physical by virtual has practical implementation challenges, and that, virtual by physical presents an interesting opportunity for immersing and engaging users.
This thesis investigates using virtual by physical constraint-based AR to validate the functionality and visuals of real-life models. We observe and identify common and representative real-world interaction constraints to include: 1D sliding, 2D planar sliding, hinged rotation, and the potential for combining these constraints. The thesis examines the functionality, interactability, and integration of these constraints in practical applications, in this case, a home decoration setting. With the results from an initial technology investigation, aiming to achieve accuracy and reliability in interactions, we have chosen marker-based AR through Vuforia with Unity3D. We have derived a systematic workflow for creation and have demonstrated successful integration of virtual objects into the real world with relevant constraints by corresponding physical objects. Our prototype results are various versions of an augmented room with distinct decorative virtual objects that are constrained by relevant physical objects where the interactions are intuitive and integrations essentially seamless. These rooms support multiple constrained objects functioning in the same environment.
Our new contributions to our field are as follows: Our categorization points to a well-defined AR application domain, virtual by physical, for investigation, where the success of the augmented rooms demonstrates the effectiveness of this category of constraint-based AR applications in validating functionality and visuals. Our formulated workflow for constructing virtual by physical constraint-based AR applications serves as an efficient and effective template for future investigations into this domain. Finally, we expand upon previous results of working with constraints in AR by demonstrating the feasibility of combining multiple types of constraints into a new constraint type.
