Align-to-Scale: Mode Switching Technique for Unimanual 3D Object Manipulation with Gaze-Hand-Object Alignment in Extended Reality

2026-03-19

AI Summary

This work addresses the challenge of performing 3D object scaling in extended reality (XR) using only one hand, a task traditionally requiring two-handed input and thus limiting mobility and convenience. The authors propose an implicit mode-switching mechanism based on the spatial alignment of gaze, hand, and target object, introducing for the first time the triadic alignment of eye–hand–object as a natural trigger condition. This enables users to scale objects through a simple one-handed pinch gesture, which can be seamlessly combined with translation for compound manipulation. By integrating gaze and gesture inputs with an alignment-detection algorithm and multiple scaling-mapping strategies, the approach significantly enhances the usability of one-handed 3D interaction in XR, as demonstrated in user studies. The findings further yield actionable design guidelines for future XR interfaces.

Technology Category

• Computer Vision: 3D Computer Vision
• Humans and AI: Interaction Techniques and Devices
• Intelligent Robots: Manipulation

Application Category

• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

As extended reality (XR) technologies rapidly become as ubiquitous as today's mobile devices, supporting one-handed interaction becomes essential for XR. However, the prevalent Gaze + Pinch interaction model partially supports unimanual interaction, where users select, move, and rotate objects with one hand, but scaling typically requires both hands. In this work, we leverage the spatial alignment between gaze and hand as a mode switch to enable single-handed pinch-to-scale. We design and evaluate several techniques geared for one-handed scaling and assess their usability in a compound translate-scale task. Our findings show that all proposed methods effectively enable one-handed scaling, but each method offers distinct advantages and trade-offs. To this end, we derive design guidelines to support futuristic 3D interfaces with unimanual interaction. Our work helps make eye-hand 3D interaction in XR more mobile, flexible, and accessible.

Problem

• unimanual interaction
• 3D object manipulation
• scaling
• extended reality
• gaze-hand alignment

Innovation

• unimanual interaction
• gaze-hand alignment
• pinch-to-scale
• mode switching
• extended reality