With the proliferation of VR and a metaverse on the horizon, many multi-user activities are migrating to the VR world, calling for effective collaboration support. As one key feature, traditional collaborative systems provide users with undo mechanics to reverse errors and other unwanted changes. While undo has been extensively researched in this domain and is now considered industry standard, it is strikingly absent for VR systems in research and industry. This work addresses this research gap by exploring different undo techniques for basic object manipulation in different collaboration modes in VR. We conducted a study involving 32 participants organized in teams of two. Here, we studied users' performance and preferences in a tower stacking task, varying the available undo techniques and their mode of collaboration. The results suggest that users desire and use undo in VR and that the choice of the undo technique impacts users' performance and social connection.

翻译：随着虚拟现实技术的普及和元宇宙的临近，众多多用户活动正迁移至虚拟现实世界，亟需有效的协作支持。传统协作系统提供撤销机制作为核心功能，允许用户逆转错误及其他非预期变更。尽管撤销功能在该领域已被广泛研究并成为行业标准，但在虚拟现实系统的研究与工业应用中却显著缺失。本研究通过探索虚拟现实不同协作模式下基本物体操作中的撤销技术，弥补了这一研究空白。我们开展了一项涉及32名参与者（两人一组）的研究，在塔式堆叠任务中考察用户在不同撤销技术与协作模式下的表现与偏好。结果表明，用户在虚拟现实中亟需并实际使用撤销功能，且撤销技术的选择会影响用户的表现与社会联系。