Beyond the Mirror: Balancing Interaction Modality and Avatar Fidelity in Public 3D Virtual Try-On Systems
Virtual Try-On (VTON) systems deployed on large public displays face a dual barrier: the physical strain of mid-air interaction and the social inhibition caused by public self-consciousness. This paper presents a real-time 3D avatar system integrating markerless motion capture with dynamic visual fidelity control to investigate and mitigate both barriers. Through a dual-study empirical evaluation, we first decoupled physical fatigue from gesture interaction ($N=20$), demonstrating that interaction fatigue is primarily driven by visuomotor latency rather than the physical act of gesturing; our optimized low-latency gesture pipeline achieved usability comparable to touchscreens while delivering superior immersion and hygiene. Building on these insights, our second study ($N=25$) investigated the "avatar fidelity paradox" via a $2 \times 2$ factorial design manipulating interaction modality (gestures vs. touch) and visual fidelity (photorealistic MetaHuman vs. stylized mannequin). Results reveal that while high fidelity and mid-air gestures independently maximize virtual embodiment ($p < .05$), their combination elicits the highest social awkwardness. Crucially, low-fidelity avatars serve as a "psychological mask" that alleviates public embarrassment during expressive gestures, while mid-air gestures simultaneously act as a compensatory mechanism to preserve perceived try-on trust despite reduced visual realism. Finally, we propose a context-aware fidelity framework to balance privacy, immersion, and commercial trust in public spatial interactions.