Abstract-This paper presents a motion planner to automatically compute animations for virtual (human, humanoid or robot) mannequins cooperating to move bulky objects in cluttered environments. The main challenge is to deal with 3D collision avoidance while preserving the believability of the agents behaviors. To accomplish the coordinated task, a geometric and kinematic decoupling of the system is proposed. This decomposition enables us to plan a collisionfree path for a reduced system, then to animate locomotion and grasping behaviors in parallel, and finally to clean up the animation from residual collisions. These three steps are automatically applied making use of different techniques such as probabilistic path planning, locomotion controllers, inverse kinematics and path planning for closed-kinematic mechanisms.