We propose a method for generating task breakpoints based on an Origin-Centric Graph (OCG) to segment goal-oriented activity recordings into task units for adaptive playback in Virtual Reality (VR) environments. With the development of Augmented Reality (AR)/VR head-mounted displays (HMDs), research on adaptive tutorials and authoring tools has become active, but existing task segmentation methods mainly rely on manual annotation or are restricted to 2D video which limits their applicability to 3D VR contexts. In our approach, assembly scenarios with clearly defined task boundaries are recorded using a structured spatio-temporal scene graph (STSG), and the OCG is employed to track changes in the central object and the formation of new groups, thereby generating task breakpoints automatically. A user study collected user-perceived task breakpoints to establish ground truth (GT), and comparison with the algorithm-detected breakpoints demonstrated high agreement and confirmed accuracy in supporting adaptive playback. The proposed task segmentation method provides a foundation for dynamically adjusting VR playback according to user proficiency and progress, with potential for extension into automatic timeline segmentation systems for diverse VR recordings.

We propose a spatial affordance-aware affine transformation method between heterogeneous spaces for continuous multi-object matching in shared Mixed Reality (MR) spaces. While previous redirection and spatial mapping approaches utilize physical objects and walkable areas, a critical gap remains in enabling continuous mapping between dissimilar physical environments that supports both precise object alignment and seamless locomotion in a shared space. Our method structurally segments heterogeneous spaces into interaction zones and constructs affine patches based on object adjacency and facing configuration, enabling continuous correspondence. We evaluate our method using a dataset of paired dissimilar spaces and demonstrate that, unlike conventional grid-based methods, our approach achieves broader spatial alignment and richer object matching. The results show that our method can serve as an effective mapping framework for shared environments requiring semantic continuity and structural coherence across diverse real-world spaces.

To enable remote Virtual Reality (VR) and Augmented Reality (AR) clients to collaborate as if they were in the same space during Mixed Reality (MR) telepresence, it is essential to overcome spatial heterogeneity and generate a unified shared collaborative environment by integrating remote spaces into a target host space. Especially when multiple remote users connect, a large shared space is necessary for people to maintain their personal space while collaborating, but the existing simple intersection method leads to the creation of narrow shared spaces as the number of remote spaces increases. To robustly align to the host space even as the number of remote spaces increases, we propose a spatial affordance-aware interactable subspace allocation algorithm. The key concept of our approach is to consider the perceivable and interactable areas separately, where every user views the same mutual space, but each remote user has a different interactable subspace, considering their location and spatial affordance. We conducted an evaluation with 900 space combinations, varying the number of remote spaces as two, four, and six, and results show our method outperformed in securing wide interactable mutual space and instantiating users compared to the other spatial matching methods. Our work enables multiple clients from diverse remote locations to access the AR host’s space, allowing them to interact directly with the table, wall, or floor by aligning their physical subspaces within a connected mutual space.

We propose Object Cluster Registration (OCR) using Geometric Spatial Affordance Graph (GSAG) to support user interaction with multiple objects in a shared space generated from two dissimilar rooms. Previous research on generating a shared virtual space from dissimilar real spaces has only reflected the information of individual objects and aimed at maximizing the area of the shared space. This led to limited interactions relying on the singular affordances of objects, neglecting to consider the usability and effectiveness of the generated shared spaces. The proposed OCR with GSAG, which considers the relationship between objects based on facing formation, extracts optimal object cluster pairs to align dissimilar rooms in generating shared virtual spaces. In an evaluation study involving 100 multi-cluster space pairs, applying OCR using GSAG showed greater effectiveness in preserving object correlations compared to cases where OCR was not used. Furthermore, the size of the shared space did not significantly differ between the two methods. This suggests that factoring in the relationship between objects does not compromise the objective of maximizing the shared virtual space. The proposed method is expected to serve as a foundation for generating shared virtual spaces that are more user-oriented and efficient by facilitating a wider range of collaborative activities for remote users in dissimilar real spaces with varied configurations.