In a collaborative work situation at a distance, the use of avatars to represent collaborators reduces collaborative effort. Also, animated avatars can help distant users to ground their relationship and facilitate their interaction because they materialise visual clues for the distant collaborators and their current activity. To check the validity of these hypotheses we set up an experiment based on the use of a collaborative virtual environment (CVE) synchronised for collective medical decision-making. Several teams of practitioners from different disciplines will (...) be required to deal with liver tumours displayed in Argonaute 3D. In this paper, we provide some evidence from existing studies for the hypotheses and select several measures to estimate the grounding process in CVEs. Next, we briefly describe the setup used to collect observable data with Argonaute 3D and we summarise first observations acquired with practitioners. (shrink)