Locomotion Interface for Outdoor Virtual Environments The Treadport Active Wind Tunnel (TPAWT pronounced teapot) is a treadmill-style locomotion interface that simulates the experience of walking outdoors. A large treadmill and display screens have been enclosed in a novel two-dimensional wind tunnel that can control the direction of wind in a frontal direction and at speeds up to 30 kph. The principles of operation and construction will be described, as well as other sensory aspects to create a realistic outdoor display.