An apparatus for interfacing 3D movements of a user to control the locomotion of an avatar in a virtual environment includes a position tracker for tracking the position of a user's feet, with the foot motions including swinging and stroking; a computer programmed for (i) computing a direction and extent of motion of a reference in the virtual environment based on the foot positions and (ii) providing an avatar corresponding to the computed direction and extent of motion; and a display for displaying the avatar in the virtual environment. The apparatus accordingly uses the gestural motion of the user's feet while seated to simulate natural human locomotion. The gestural motions of stroking and swinging include translational and rotating movements, and are chosen to correspond to the actions of the feet and legs during natural human locomotion, providing natural control of virtual locomotion. The apparatus is also designed for controlling the locomotion of a remote vehicle.