We present two experiments to assess the relative impact of different levels of body animation fidelity on plausibility illusion (Psi). The first experiment presents a virtual character that is not controlled by the user ( $n=13$ ), while the second experiment presents a user-controlled virtual avatar ( $n=24$ , all male). Psi concerns how realistic and coherent the events in a virtual environment look and feel and is part of Slater's proposition of two orthogonal components of presence in virtual reality (VR). In the experiments, the face, hands, upper and lower bodies of the character or self-avatar were manipulated to present different degrees of animation fidelity, such as no animation, procedural animation, and motion captured animation. Participants started the experiment experiencing the best animation configuration. Then, animation features were reduced to limit the amount of captured information made available to the system. Participants had to move from this basic animation configuration towards a more complete one, and declare when the avatar animation realism felt equivalent to the initial and most complete configuration, which could happen before all animation features were maxed out. Participants in the self-avatar experiment were also asked to rate how each animation feature affected their sense of control of the virtual body. We found that a virtual body with upper and lower body animated using eight tracked rigid bodies and inverse kinematics (IK) was often perceived as equivalent to a professional capture pipeline relying on 53 markers. Compared to what standard VR kits in the market are offering, i.e., a tracked headset and two hand controllers, we found that foot tracking, followed by mouth animation and finger tracking, were the features that added the most to the sense of control of a self-representing avatar. In addition, these features were often among the first to be improved in both experiments.

中文翻译：

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虚拟现实中虚拟身体动画特征的合理性

我们提出了两个实验来评估不同级别的身体动画保真度对似真性错觉 (Psi) 的相对影响。第一个实验呈现了一个不受用户控制的虚拟角色（ $n=13$ )，而第二个实验展示了一个用户控制的虚拟化身 ( $n=24$ ，都是男性）。Psi 关注虚拟环境中事件的外观和感觉的真实性和连贯性，是 Slater 提出的虚拟现实 (VR) 中存在的两个正交组件的一部分。在实验中，对角色或自我化身的面部、手部、上下身进行了操作，以呈现不同程度的动画保真度，例如无动画、程序动画和动作捕捉动画。参与者开始体验最佳动画配置的实验。然后，减少动画功能以限制系统可用的捕获信息量。参与者必须从这个基本的动画配置转向更完整的配置，并声明头像动画的真实感何时感觉等同于初始和最完整的配置，这可能发生在所有动画功能被最大化之前。自我化身实验的参与者还被要求评估每个动画特征如何影响他们对虚拟身体的控制感。我们发现，使用 8 个跟踪刚体和反向运动学 (IK) 为上下半身设置动画的虚拟身体通常被认为等同于依赖 53 个标记的专业捕捉管道。与市场上提供的标准 VR 套件（即一个跟踪头显和两个手控制器）相比，我们发现足部跟踪、嘴部动画和手指跟踪是最能增加控制感的功能。自我代表的化身。此外，这些功能通常是两个实验中最先得到改进的功能之一。自我化身实验的参与者还被要求评估每个动画特征如何影响他们对虚拟身体的控制感。我们发现，使用 8 个跟踪刚体和反向运动学 (IK) 为上下半身设置动画的虚拟身体通常被认为等同于依赖 53 个标记的专业捕捉管道。与市场上提供的标准 VR 套件（即一个跟踪头显和两个手控制器）相比，我们发现足部跟踪、嘴部动画和手指跟踪是最能增加控制感的功能。自我代表的化身。此外，这些功能通常是两个实验中最先得到改进的功能之一。自我化身实验的参与者还被要求评估每个动画特征如何影响他们对虚拟身体的控制感。我们发现，使用 8 个跟踪刚体和反向运动学 (IK) 为上下半身设置动画的虚拟身体通常被认为等同于依赖 53 个标记的专业捕捉管道。与市场上提供的标准 VR 套件（即一个跟踪头显和两个手控制器）相比，我们发现足部跟踪、嘴部动画和手指跟踪是最能增加控制感的功能。自我代表的化身。此外，这些功能通常是两个实验中最先得到改进的功能之一。