Stretch your reach: Studying Self-Avatar and Controller Misalignment in Virtual Reality Interaction

Title of the Paper

Stretch your reach: Studying Self-Avatar and Controller Misalignment in Virtual Reality Interaction

Paper Information

• Subject Area: Research on self-avatar and controller misalignment in virtual reality interaction
• Keywords: Virtual reality, 3D interaction, virtual avatar, perception, self-avatar

Research Background and Problem Statement

• Identified Issues or Challenges:
  When users interact with virtual objects in virtual reality applications, high embodiment requires the virtual body’s movements to align with the user’s actual movements. However, due to factors such as the size of the virtual avatar and skeletal simplifications, misalignments may occur between the virtual body and the user’s physical body, especially concerning hand and controller positioning. Such misalignments can negatively impact user experience and interaction accuracy.

• Significance:
  The challenge of correctly aligning the virtual body not only affects users’ perception of self-avatar embodiment but also influences task performance and interaction preferences. Therefore, addressing the issue of misalignment between the virtual avatar and controller is crucial for enhancing the quality of virtual reality experiences.

• Research Motivation and Related Work:
  Existing studies have explored the impact of certain virtual hand, arm, and body representations on embodiment. Early research has also investigated hand positioning offset techniques. However, there is a lack of in-depth exploration of the effects of full-body virtual avatars on interactions with virtual objects.

Proposed Solution

• Proposed Method or Solution:
  Five interaction modes were proposed to address the issue of misalignment between the virtual avatar and controller, and their effects on embodiment, proprioception, user preferences, and task performance were studied. These five modes were designed based on the rendering and positioning of the virtual controller, including:

  • FreeController: Only the controller is rendered, but its position may be separate from the virtual hand.
  • AttachedController: The controller is always bound to the virtual hand, though misalignment may occur.
  • Hand: The virtual controller is not rendered, and interaction occurs solely through the virtual hand.
  • StretchController: The virtual arm is stretched to align with the real arm, while the controller is rendered.
  • StretchHand: Similar to StretchController, but the virtual controller is not rendered.

• Innovative Aspects:
  A novel interaction design was proposed that simultaneously considers visual feedback and body continuity, particularly by dynamically extending the virtual arm to address misalignment between the avatar and the physical controller.

• Implementation Steps:
  A virtual environment was built using Unity, and experiments were conducted to validate the effects of different modes on embodiment, user preferences, and task performance. The following interaction tasks were designed for evaluation:

  • Cube Task: Picking up and placing virtual cubes labeled with letters.
  • Cannonball Task: Catching virtual balls moving in different directions and speeds.
  • Drawing Board Task: Using a virtual brush to draw simple shapes on a virtual whiteboard.

Research Outcomes

• Specific Findings:

  • The Stretch modes demonstrated the best performance in terms of embodiment, user preferences, proprioception, and task performance.
  • Whether or not the controller was rendered had little significant impact on embodiment and user preferences.
  • Multi-sensory feedback (visual and tactile consistency) was not essential; in fact, misalignment could reduce the effectiveness of avatar embodiment.

• Advantages Compared to Existing Solutions:

  • The proposed Stretch modes not only resolved the issue of avatar-controller misalignment but also avoided perceptual conflicts for users, thereby improving the overall interaction experience.
  • The method is easy to implement and can be combined with existing technologies, such as inverse kinematics, to achieve dynamic stretching.

• Experimental or Evaluation Results:

  • Data were processed using non-parametric statistical analysis and mixed-effects models.
  • The StretchController and StretchHand modes significantly improved embodiment, proprioception, and task performance.

• Limitations and Future Directions:

  • Limitations: The study primarily focused on specific virtual interaction tasks, which may not fully generalize to all types of virtual reality applications. Additionally, participant backgrounds and technical setups could influence the results.
  • Future Directions: The research could be extended to collaborative tasks or inclusive design in virtual reality. For example, the stretching modes could be adapted to improve interaction experiences for users with mobility impairments.