1. A method of preparing data for displaying a surface of an n-dimensional body, n being at least 3, the method comprising the steps of: obtaining an n-dimensional discrete mesh representation of the surface, the mesh representation of the surface comprising a plurality of boundary nodes, each boundary node lying on or adjacent to the surface, each boundary node being associated with connectivity information preferably comprising representations of up to (n−1) incoming and/or up to (n−1) outgoing directions towards 2*(n−1) adjacent boundary nodes adjacent to the said boundary node, the directions being defined in such a way that the cross product of the up to n−1 incoming or outgoing directions associated with any boundary node represents a further vector which points away from the surface at that boundary node.