Describes a series of stages in the development of a new virtual locomotion device that has been designed to enhance remote inter-personal communications. The latest system, called GSS (Ground Surface Simulator), inherits the features of two previous locomotion interfaces, viz. ATLAS (ATR Locomotion interface for Active Self-motion) and ALF (ALive Floor). GSS also incorporates two different features not found in ordinary treadmills: a movable belt and an active belt-speed controller. We built an initial prototype of GSS and developed a method that presents bumpy surfaces that are free from the mechanical limitations inherent in prior designs. Experimental results showed that a subject could distinguish a 1% difference in the virtual slope on the GSS.