We present a technique for the optical design of generalized-distribution GRIN lenses. Multi-element homogeneous lens designs are reconstructed as single GRIN media via smoothing of the homogeneous lens paraxial ray paths. These continuous optical systems successfully replicate the first-order properties of their homogeneous parent lens systems and serve as starting points for further optimization. When the technique is applied at several wavelengths, the chromatic aberration correction of the homogeneous parent lens is also converted. The paraxial reconstruction, finite-ray optimization, and evaluation of several lens designs are demonstrated.@en