Although the iterative closest point algorithm is very effective in registering range data, the quality of registration depends on the geometry of the sampled surfaces. This work presents a registration aid which can greatly reduce the possibility of catastrophic registration failure, increase the quality of registration and register range data which does not overlap. By placing the aid into the scene along with the object(s) of interest, range images taken from any vantage point within the range scanner's workspace can be registered onto a model of the aid and thus into a common reference frame. By considering the causes of registration failure, the surface of the aid is designed so that any range image taken of it from any point in the scanner's workspace will properly register with a model of the aid. The reliability of the aid is demonstrated with a Monte Carlo experiment and its utility is demonstrated with examples from an automated surface acquisition system.