Computer aided design of a prosthesis for a below-the-knee (trans-tibial) amputee begins with a digitized representation of the shape of the residual limb. Certain anatomical landmarks must be located on this shape to identify optimal areas for load and pressure relief. A method of locating the midpoint of the patellar tendon, the distal end of the tibia and the head of the fibula is presented. The method involves training ensembles of neural networks on shapes for which the markers have been located manually; the neural networks are then used to find the landmarks for arbitrary shapes. Experimental results show that the method is at least as accurate as a trained prosthetist.