SWIMVR: Simulating Water Interaction Using Multimodal Vibro-Thermal Rendering

Reproducing realistic fluid interactions in Virtual Reality (VR) remains an open challenge due to their dynamic and multimodal nature. In this paper, we introduce SWIMVR, a wearable vibro-thermal haptic glove that simulates handwater interactions in VR through coordinated cold thermal and vibrotactile feedback. SWIMVR delivers event-driven, spatiotemporally modulated actuation to render both surface impact and submerged flow sensations. Built around 14 micro-thermoelectric cooling modules and 13 vibrotactile actuators per hand, the system operates in real-time with a VR ocean environment rendered in Unity. We conducted two user studies optimizing thermal waveform patterns for perceptual stability and comfort, and actuator layouts for perceptual fidelity with minimal hardware. Results show that triangular thermal modulation, achieved by cycling between two cooling levels rather than maintaining a fixed output, yields the most perceptually stable cold sensations, while a reduced actuator configuration closely matches the full hand in spatial coverage and subjective realism. A follow-up study con-firmed that palmar-only actuation can evoke cold sensations on the dorsal side, allowing further hardware reductions. SWIMVR demonstrates that timing and spatial targeting of multimodal cues can produce strong subjective impressions of water interaction in VR, offering a pathway towards scalable, untethered haptic feedback for immersive environments.