Sharing one object between several users is a strong problem in distant environment, for example with a coordinated complex teleoperation on one but complex robot, or with the feedback of another user's action in a VR world, while it's natural in a local and real environment.

We consider here the case of several users that have to coordinate their actions in a Virtual World.

Through the VIRAT platform, we are building experiments in order to evaluate the best paradigms of interaction: how to represent other users, how to obtain a feedback (force, visual, sound, etc.) from their actions, how to handle mistakes due to interfaces imprecision's or network latencies, etc..
As a consequence, we are developing for example new interfaces and metaphors, or also tools that adapt the best interfaces according to the current users and their context.