Vibr-eau: Emulating Fluid Behavior in Vessel Handling through Vibrotactile Actuators

TL;DR

Vibr-eau addresses the challenge of scalable, durable haptic feedback for virtual fluids in VR by using a compact, multi-motor vibrotactile setup embedded in a 3D-printed vessel. It maps the virtual liquid's center of gravity to spatially and temporally asymmetric motor activations, synchronized to fluid motion, within Unity using Obi Fluid for real-time dynamics. Two user studies show that Vibr-eau can convey dynamic weight shifts and liquid-like sensations, achieving object realism comparable to real liquid and generalizing across vessel shapes, while revealing limitations in timing consistency and dependence on visual cues. The work suggests that multi-motor vibrotactile rendering can enable realistic, scalable haptic experiences for virtual fluids with broad applications in VR gaming, education, and training.

Abstract

Existing methods of haptic feedback for virtual fluids are challenging to scale, lack durability for long-term rough use, and fail to fully capture the expressive haptic qualities of fluids. To overcome these limitations, we present Vibr-eau, a physical system designed to emulate the sensation of virtual fluids in vessels using vibrotactile actuators. Vibr-eau uses spatial and temporal vibrotactile feedback to create realistic haptic sensations within a 3D-printed vessel. When the users are in the virtual environment and interact with the physical vessel, vibration impulses are triggered and the user will feel like there is fluid in the vessel. We explore the impact of motor density, direct touch, and vibration strength on users' perception of virtual fluid sensations. User studies reveal that Vibr-eau effectively simulates dynamic weight shifts and fluid-like sensations, with participants reporting experiences closely resembling real-world interactions with fluids. Our findings contribute to the development of adaptable and scalable haptic applications for virtual fluids, providing insights into optimizing parameters for realistic and perceptually faithful simulated fluid experiences in VR environments.

Figures (13)

• Figure 1: Vibr-eau's System Diagram
• Figure 2: Electronic Schematic: a Nano board is mounted on a perma-proto board. Up to 8 vibration motors with male jumper cables can be connected to the 8 female jumper cables extending from the nano board.
• Figure 3: Left: The Vibr-eau system comprising of the Vive Tracker, electronics, and a 3D-printed physical vessel, with motor placement highlighted in light gray. Right: The virtual vessel filled with liquid, with invisible game objects strategically positioned on the bottom of the vessel to correspond with their respective physical motors.
• Figure 4: Single contact microphone recording: Acoustic vibration samples of single action recorded with a contact microphone in the form of digital audio signals for a plastic water bottle, a metal cup, and a glass flask. All samples are 400 ms long and in the same amplitude (y-axis) scale
• Figure 5: Two contact microphone recording: Acoustic vibration samples of single action recorded with two contact microphones in the form of digital audio signals for a plastic water bottle, a metal cup, and a glass flask. All samples are 400 ms long and in the same amplitude (y-axis) scale. Blue for left, Orange for right.