In many collaborative virtual reality applications, co-located users often have their relative position in the virtual environment matching the one in the real world. The resulting spatial consistency facilitates the co-manipulation of shared tangible props and enables the users to have direct physical contact with each other. However, these applications usually exclude their individual virtual navigation capability, such as teleportation, as it may break the spatial configuration between the real and virtual world. As a result, the users can only explore the virtual environment of approximately similar size and shape compared to their physical workspace. Moreover, their individual tasks with unlimited virtual navigation capability, which often take part in a continuous workflow of a complex collaborative scenario, have to be removed due to this constraint. This work aims to help overcome these limits by allowing users to recover spatial consistency after individual teleportation in order to re-establish their position in the current context of the collaborative task. We use a virtual representation of the user’s shared physical workspace and develop two different techniques to position it in the virtual environment. The first technique allows one user to fully position the virtual workspace, and the second approach enables concurrent positioning by equally integrating the input from all the users. We compared these two techniques in a controlled experiment in a virtual assembly task. The results show that allowing two users to manipulate the workspace significantly reduced the time they spent negotiating the position of the future workspace. However, the inevitable conflicts in simultaneous co-manipulation were also a little confusing to them.

Industrial design review is an iterative process which mainly relies on two steps involving many stakeholders: design discussion and CAD data adjustment. We investigate how a wall-sized display could be used to merge these two steps by allowing multidisciplinary collaborators to simultaneously generate and explore design alternatives. We designed ShapeCompare based on the feedback from a usability study. It enables multiple users to compute and distribute CAD data with touch interaction. To assess the benefit of the wall-sized display in such context, we ran a controlled experiment which aims to compare ShapeCompare with a visualization technique suitable for standard screens. The results show that pairs of participants performed a constraint solving task faster and used more deictic instructions with ShapeCompare. From these findings, we draw generic recommendations for collaborative exploration of alternatives.

Teleportation is a navigation technique widely used in virtual reality applications using head-mounted displays. Basic teleportation usually moves a user’s viewpoint to a new destination of the virtual environment without taking into account the physical space surrounding them. However, considering the user’s real workspace is crucial for preventing them from reaching its limits and thus managing direct access to multiple virtual objects. In this paper, we propose to display a virtual representation of the user’s real workspace before the teleportation, and compare manual and automatic techniques for positioning such a virtual workspace. For manual positioning, the user adjusts the position and orientation of their future virtual workspace. A first controlled experiment compared exocentric and egocentric manipulation techniques with different virtual workspace representations, including or not an avatar at the user’s future destination. Although exocentric and egocentric techniques result in a similar level of performance, representations with an avatar help the user to understand better how they will land after teleportation. For automatic positioning, the user selects their future virtual workspace among relevant options generated at runtime. A second controlled experiment shows that the manual technique selected from the first experiment and the automatic technique are more efficient than the basic teleportation. Besides, the manual technique seems to be more suitable for crowded scenes than the automatic one.

A method that allows quick estimation of Redirection Detection Thresholds (RDTs) is not only useful for identifying factors that contribute to the detection of redirections, but can also provide timely inputs for personalized redirected walking control. In aim to achieve quick RDT estimation, we opted for a classical psychophysical method - the Method of Adjustment (MoA), and compared it against commonly used method for RDT estimation (i.e. MCS-2AFC) to see their difference. Preliminary results show that MoA allows to save about 33% experiment time when compared with MCS-2AFC while getting overall similar RDT estimations on the same population.

In a Multi-stereoscopic immersive system, several users sharing the same restricted workspace, e.g. a CAVE, may need to perform independent navigation to achieve loosely coupled collaboration tasks for a complex scenario. In this context, a proper navigation paradigm should provide users both an efficient control of virtual navigation and a guarantee of users' safety in the real workspace relative to the display system and between users. In this aim, we propose several alterations of the human joystick metaphor by introducing implicit adaptive control to allow safe individual navigation for multiple users. We conducted a user study with an object-finding task in a double-stereoscopic CAVE-like system to evaluate both users' navigation performance in the virtual world and their behavior in the real workspace under different conditions. The results highlight that the improved paradigm allows two users to navigate independently despite physical system limitations.

This paper describes a global interactive framework enabling an automatic path-planner and a user to collaborate for finding a path in cluttered virtual environments. First, a collaborative architecture including the user and the planner is described. Then, for real time purpose, a motion planner divided into different steps is presented. First, a preliminary workspace discretization is done without time limitations at the beginning of the simulation. Then, using these pre-computed data, a second algorithm finds a collision free path in real time. Once the path is found, an haptic artificial guidance on the path is provided to the user. The user can then influence the planner by not following the path and automatically order a new path research. The performances are measured on tests based on assembly simulation in CAD scenes.

This paper describes a global interactive scheme including fast motion planning and real time guiding force for 3D CAD part assembly or disassembly tasks. For real time purpose, the motion planner is divided into different steps. First, a preliminary workspace discretization is done without time limitations at the beginning of the simulation. Then, using those computed data, a second part tries to find a collision free path in real time. Once the path is found, an haptic artificial force is applied constraining the user on the path. The user can then influence the planner by not following the path and automatically order a new path research. The performance of this haptic assistance is measured on a test simulation based on an ALSTOM power components assembly simulation.