Unbounded: Object-Boundary Interactions in Mixed Reality

Paper Title

Unbounded: Object-Boundary Interaction in Mixed Reality

Publication Info

• Topic area: Mixed Reality (MR) interaction design focusing on object-boundary relationships.
• Keywords: Mixed Reality, object-boundary interaction, design space, augmented reality, virtual reality, tangible interfaces, interaction design, spatial computing, human-computer interaction, extended reality.

Background and Problem

• Problem / challenge: Existing MR research often focuses on specific boundary phenomena (e.g., portals, mirrors) but lacks a comprehensive framework that treats object-boundary relationships as a design material. This limits the exploration of novel interactions that transcend physical constraints.
• Significance: Boundaries are ubiquitous in the physical world, and reimagining their role in MR could unlock new interaction paradigms, enriching productivity, creativity, and user experiences.
• Motivation and related work: Prior work has explored boundary-related phenomena like making walls transparent or pulling objects from 2D screens, but these remain context-specific. This paper builds on these efforts to propose a broader, system-agnostic framework for object-boundary interaction (OBI) in MR.

Solution

• Proposed approach: The authors introduce "Unbounded," a Research through Design (RtD) inquiry that articulates a design space for object-boundary interaction (OBI) in MR, accompanied by eight demonstrative examples.
• Novelty:
  1. Development of a comprehensive design space for OBI, encompassing object, boundary, and human interaction dimensions.
  2. Introduction of a visual design language to encode and communicate interaction elements.
  3. Implementation of eight functional examples across productivity and art exploration scenarios to demonstrate the framework's generative potential.
  4. Expert feedback sessions to refine the framework and expand its conceptual scope.
• Procedure and key techniques:
  • Iterative development of the design space through sketches, group feedback, and expert sessions.
  • Creation of a visual design language with symbols for object, boundary, and human attributes.
  • Implementation of eight MR prototypes using Meta Quest 3 and Unity, covering scenarios like interactive painting, paper shredding, and acoustic partitions.
  • Semi-structured feedback sessions with six MR experts to evaluate the framework's clarity, usefulness, and potential extensions.

Results

• Concrete findings:
  • The framework clarified object-boundary-human relationships and revealed new interaction possibilities.
  • Experts appreciated the generative potential of the framework, particularly in artistic and speculative contexts.
  • Examples like the Magic Mirror and Interactive Painting were praised for their metaphorical clarity and expressive potential.
• Advantage over baselines:
  • Unlike prior work, Unbounded provides a system-agnostic, comprehensive framework that emphasizes experiential richness and designerly intentionality.
  • The framework bridges physical and digital interactions, enabling seamless integration of MR into everyday life.
• Experiments / evaluation:
  • Conducted expert feedback sessions with six MR professionals, each with 4+ years of experience, focusing on the framework's clarity, completeness, and generative power.
  • Evaluated eight functional prototypes across two scenarios (Productivity and Art Exploration) to demonstrate the framework's applicability.
• Limitations and future work:
  • The study relied on video demonstrations and slide walkthroughs, limiting the embodied understanding of interactions.
  • Future work could include hands-on user studies, workshops to test the framework's generative power, and exploration of social acceptability in public spaces.
  • Further research could investigate multi-user interactions, animation strategies, and more-than-human design.

Summary

The paper introduces "Unbounded," a framework for object-boundary interaction (OBI) in mixed reality (MR), addressing gaps in prior research by treating boundaries as a design material. The authors developed a design space and visual language, implemented eight functional examples, and conducted expert feedback sessions to refine the framework. Key findings highlight the potential of OBI to enrich MR interactions by bridging physical and digital worlds, enabling speculative and artistic experiences while maintaining interaction clarity. The study emphasizes the importance of balancing practicality and imagination in MR design. Future work aims to expand the framework's generative power and explore its application in diverse contexts.