The present invention is a Distally Assembled Steerable Cannula (DASC), a robotically-manipulated device that can be deployed and extended within a patients body by growing from its distal end, or can be used in non-medical applications. In one embodiment, growth occurs by sequentially assembling segments that interlock to form a rigid tube with a complex 3-D shape. The segments are individually transported through the growing cannula, and then assembled at the distal end. A segment can be wedge-shaped in profile, allowing adjustment of the local radius of curvature and direction of the cannula to be controlled by relative segment orientation.
