Abstract: An apparatus for controlling an interactive virtual environment is disclosed. The apparatus comprises means for defining a virtual environment populated by objects, the objects comprising at least avatars and props, objects within the virtual environment may be dynamically attached to and detached from other objects under user control. A prop has associated with it an animation for use when an avatar interacts with the prop, and when the prop is attached to another object the animation remains associated with the prop. When an object is attached to another object, it may inherit the movement of the object to which it is attached.