Implementing flexible rules of interaction for object manipulation in cluttered virtual environments

Object manipulation in cluttered virtual environments (VEs) brings additional challenges to the design of interaction algorithms, when compared with open virtual spaces. As the complexity of the algorithms increases so does the flexibility with which users can interact, but this is at the expense of much greater difficulties in implementation for developers. Three rules that increase the realism and flexibility of interaction are outlined: collision response, order of control, and physical compatibility. The implementation of each is described, highlighting the substantial increase in algorithm complexity that arises. Data are reported from an experiment in which participants manipulated a bulky virtual object through parts of a virtual building (the piano movers’ problem). These data illustrate the benefits to users that accrue from implementing flexible rules of interaction.