Thermal feedback is critical to a range of Virtual Reality (VR) applications, such as firefighting training or thermal comfort simulation. Previous studies showed that adding congruent thermal feedback positively influences User eXperience (UX). However, existing work did not compare different levels of thermal feedback quality and mostly used less immersive virtual environments. To investigate these gaps in the scientific literature, we conducted a within-participant user study in two highly-immersive scenarios, Desert Island (n=25) and Snowy Mountains (n=24). Participants explored the scenarios in three conditions (Audio-Visual only, Static-Thermal Feedback, and Dynamic-Thermal Feedback). To assess the complex and subtle effects of thermal feedback on UX, we performed a multimodal analysis by crossing data from questionnaires, semi-structured interviews, and behavioral indicators. Our results show that despite an already high level of presence in the Audio-Visual only condition, adding thermal feedback increased presence further. Comparison between levels of thermal feedback quality showed no significant difference in UX questionnaires, however this result is nuanced according to participant profiles and interviews. Furthermore, we show that although the order of passage did not influence UX directly, it influenced user behavior. We propose guidelines for the use of thermal feedback in VR, and the design of studies in complex multisensory scenarios.

翻译：热反馈对于一系列虚拟现实（VR）应用（如消防训练或热舒适模拟）至关重要。先前研究表明，添加一致的热反馈对用户体验（UX）有积极影响。然而，现有研究未比较不同热反馈质量水平，且大多使用沉浸感较低的虚拟环境。为探究科学文献中的这些空白，我们在两个高度沉浸式场景（“荒岛”，n=25；“雪山”，n=24）中开展了一项被试内用户研究。参与者在三种条件下（仅视听、静态热反馈、动态热反馈）探索场景。为评估热反馈对UX的复杂且微妙的影响，我们通过交叉分析问卷、半结构化访谈和行为指标数据进行了多模态分析。结果表明，尽管在仅视听条件下存在感已处于较高水平，添加热反馈仍能进一步提升存在感。热反馈质量水平间的比较在UX问卷上未显示出显著差异，但根据参与者画像和访谈，这一结果存在细微差别。此外，我们发现，尽管体验顺序未直接影响UX，但它影响了用户行为。我们提出了在VR中使用热反馈的指南，以及复杂多感官场景研究的设计建议。