;I general paradigm for recognizing 3D objects is offered, and applied to some geometric primitives [sphe,res, cylinders, cones, and tori). The assumption is that Q curve on the surface WQS measured with high accuracy (for instance, by a sensory robot). Differential properties of curves and surfaces are used to recognize the surface. The motivation is t,wofold: the output of some devices is not surface range data, but such curves. So, surface invariants, which may be simpler in some cases, cannot Q ~ W Q Y Sbe obtained. Also, a consaderable speedup is obtained by using curve data, QS opposed to surface data which usually contains Q much higher number of points.