This paper presents a new technique for controlling a user's navigation in a virtual environment.The approach introduces artificial force fields which act upon the user's virtual body such that he is guided around obstacles, rather than penetrating or colliding with them.The technique is extended to incorporate gravity into the environment.The problem of negotiating stairs during a walk-through has also been investigated with the new approach.Human subjects were tested in experiments in which they experienced three different kinds of navigation: unconstrained, simple constrained and assisted by force fields.Theresults demonstrate that the force-field technique is an effective approach for effective, comfortable navigation.