Virtual reality offers ordinary users the ability to observe and interact with various abstract or concrete objects visualized in a three-dimensional space from different angles. Users can manipulate, transform, or reconstruct these objects similarly to how they might in a real environment. Manipulating objects in virtual reality is not as effortless as in the real world, due to the lack of sensory feedback and limited input freedom. However, it also offers new advantages that the real world cannot provide, such as the ability to easily select and control remote objects and the support of various auxiliary user interfaces. In particular, when it is necessary to alternately manipulate objects of various sizes, scaling the user’s avatar symmetrically allows for more effective manipulation than in the real world. However, manual scaling interfaces can be cumbersome and may induce dizziness. This study proposes an interaction technique that allows users to conveniently manipulate objects of various sizes without manual scale adjustment, by automatically and instantly adjusting the scale factor according to the size of the selected object and its adjacent objects. To compensate for the change in scale, we also implement a position correction mechanism that adjusts the user’s position in the virtual environment. Preliminary experiments with a small group of participants confirmed that automatic scale adjustment produces significant effects. Based on the feedback from these experiments, a more refined distance calculation method and the timing for scale adjustment were derived. In the main experiment with 14 participants, it was confirmed that the automatic scale adjustment method proposed in this study led to higher accuracy and lower discomfort in task completion compared to the conventional manual scale adjustment method. We expect that the results of this study will effectively contribute to the creation of virtual reality content that requires interaction with objects of various sizes in the future.

As VR technology advances and network speeds rise, social VR platforms are gaining traction. These platforms enable multiple users to socialize and collaborate within a shared virtual environment using avatars. Virtual reality, with its ability to augment visual information, offers distinct advantages for collaboration over traditional methods. Prior research has shown that merely sharing another person’s viewpoint can significantly boost collaborative efficiency. This paper presents an innovative non-verbal communication technique designed to enhance the sharing of visual information. By employing virtual cameras, our method captures where participants are focusing and what they are interacting with, then displays these data above their avatars. The direction of the virtual camera is automatically controlled by considering the user’s gaze direction, the position of the object the user is interacting with, and the positions of other objects around that object. The automatic adjustment of these virtual cameras and the display of captured images are symmetrically conducted for all participants engaged in the virtual environment. This approach is especially beneficial in collaborative settings, where multiple users work together on a shared structure of multiple objects. We validated the effectiveness of our proposed technique through an experiment with 20 participants tasked with collaboratively building structures using block assembly.