Finite element modelling of fields within the body, whether electrical or optical, requires knowledge of the geometry of the object being examined. It can be clinically impractical to obtain accurate surface information for individual patients, although a limited set of measurements such as the locations of sensors attached to the body, can be acquired more readily. In this paper, we describe how a generic surface taken from an adult head is warped to fit points measured on a neonatal head surface to provide a new, individual surface from which a finite element mesh was generated. Simulations show that data generated from this mesh and from the original neonatal head surface are similar to within experimental errors. However, data generated from a mesh of the best fit sphere were significantly different from data generated from the original neonatal head surface.