Design and Evaluation of Dual-Thumb 3D Interaction Framework for Large Tablet in Augmented Reality

Interaction with 3D objects in Augmented Reality (AR) on tablets is increasingly common, yet most existing systems rely on single-handed input, causing occlusion, fatigue, and device instability. Using both hands to hold the tablet alleviates these issues. This article introduces a dual-thumb interaction framework that enhances both selection and manipulation of 3D AR content. We first propose the 3D Parabolic Ray Pointing technique, where thumb movements along the X, Y, and Z axes control the landing point for distant pointing. Comparative experiments show that this method reduces fatigue and is preferred over existing techniques. We then develop two dual-thumb techniques for 3D object selection and manipulation: (1) Planar WiM Selection with Steering Wheel Manipulation and (2) WiM-Based Selection and Manipulation. Evaluations across various tasks reveal complementary advantages. Finally, we implement these techniques in an AR sandbox application, demonstrating the framework's potential for broader adoption.