User-Empowered Head Movement Techniques in Virtual Reality (VR)

Cover image: Head Rotation Amplification

As part of my Master's thesis in Human-Computer Interaction (HCI) at Umeå University, supervised by Prof. Anders Lundström, I explored novel head rotation amplification techniques in Virtual Reality (VR) specifically designed to overcome the challenges posed by physically restricted turning angles in seated VR environments. The project focused on exploring novel head rotation techniques enhancing user comfort, efficiency, and overall interaction experience.

Abstract

In seated virtual reality (VR), where large physical turns are limited, altering the mapping between physical and virtual movements can amplify head rotation, enabling efficient view control with reduced physical effort. This thesis introduces two amplified head rotation (AHR) techniques for seated VR: the user-empowered Interactive, which affords user-timed switching between high and low gain, and Adaptive, which adjusts gain automatically based on head-motion kinematics. We evaluated both techniques in a mixed-methods study (n = 31), compared with a Static constant-gain baseline (g = 2.5) across a head-pointing task and a 180° rotation task. Both Interactive and Adaptive improved head-pointing performance relative to Static, while increasing physical head movement; cybersickness remained low and virtual–physical heading offsets were generally modest. Qualitatively, participants valued Interactive for the agency and control it afforded. Notably, this control enabled an emergent behavior in which users intentionally reoriented the virtual view via asymmetric rotational gains — a user-initiated redirection strategy we term ViewShift. Adaptive reduced cognitive load but could occasionally misalign with user intent. Together, the findings suggest potential for giving users control over rotational gains and highlight visible, user-centered AHR as an interaction technique for seated VR.

Implemented Prototype in Unity 3D

Techniques Developed

Static Gain (Baseline)

Static amplification: Physical head rotation multiplied by a fixed factor. For example, a 30° turn becomes 60° in VR (gain = 2).

Interactive (User‑Empowered) Gain

Interactive amplification: Users manually toggle between high and 1:1 normal mapping using VR controllers during ballistic (rapid rotation) and corrective phases for higher accuracy.

Adaptive Gain

Dynamic adaptive amplification: Automatic gain adjustment based on head rotation velocity and acceleration to smoothly transition between high gain during ballistic movements and normal gain during precise alignment.

Study Design

We conducted a mixed-methods, within-subjects evaluation comparing three rotational gain techniques for seated VR: Constant (fixed gain 2.5×), Interactive (user-timed switching), and Adaptive (automatic adjustment based on head-motion kinematics).
31 participants performed two tasks (head-pointing and 180° rotation) under all techniques in randomized order.

Metrics Collected

Task Completion Time: Time required to complete tasks.
Error Rate: The number of times targets were missed, and the angular deviation from the intended target.
Accumulated Offset: The overall angular difference between the task's starting and ending positions within the virtual environment.
Physical vs. Virtual Accumulated head Movement: Accumulated angular head movements were measured in both the physical and virtual environments.
NASA-TLX: User workload assessment.
Cybersickness in Virtual Reality Questionnaire (CSQ-VR): Used to assess the level of motion sickness experienced in virtual reality across different techniques.

Usability Questions Regarding

Comfort and Usability: User comfort levels and intuitive interaction.
Control and Precision: User comfort levels and the ease of interaction during tasks.
Naturalness and Applicability: How naturally the techniques felt and how applicable users found them for VR use.

Qualitative User Feedback

User feedback was gathered through semi-structured interviews to explore the following areas:

How users experienced amplified head rotation compared to normal 1:1 mapping.
How head rotation amplification affected users' sense of direction and spatial orientation.
Preferences between different amplification techniques (interactive vs. adaptive).
The impact of head rotation amplification on users' sense of immersion in the virtual environment.

The interviews included questions about users' overall experience with each technique, perceived control and speed, ease of targeting, feelings of discomfort or motion sickness, and preferences for interactive versus adaptive amplification. Participants were also asked about their perception of space and immersion while using amplified head rotation.

The qualitative data was analyzed using thematic analysis, which allowed me to identify key patterns and insights regarding user experiences and preferences related to head rotation amplification in VR.

Tasks

Head Rotation Amplification, 180° Rotation Task — 180° Rotation Task

Head Rotation Amplification, Small Bubbles Task (90° and 180° Conditions) — Small Bubbles Task (90° and 180° Conditions)

Resources & Further Reading