Investigating Size Congruency Between the Visual Perception of a VR Object and the Haptic Perception of Its Physical World Agent

Sandplay is an effective psychotherapy for mental retreatment, and many people prefer to engage in sandplay in Virtual Reality (VR) due to its convenience. Haptic perception of physical objects and miniatures enhances the realism and immersion in VR. Previous studies have rendered sizes by exerting pressure on the user’s fingertips or employing tangible, shape-changing devices. However, these interfaces are limited by the physical shapes they can assume, making it difficult to simulate objects that grow larger or smaller than the interface. Motivated by literature on visual-haptic illusions, this work aims to convey the haptic sensation of a virtual object’s shape to the user by exploring the relationships between the haptic feedback from real objects and their visual renderings in VR. Our study focuses on the confirmation and adjustment ratios for different virtual object sizes. The results show that the likelihood of participants confirming the correct size of virtual cubes decreases as the object size increases, requiring more adjustments for larger objects. This research provides valuable insights into the relationships between haptic sensations and visual inputs, contributing to the understanding of visual-haptic illusions in VR environments.