The GRworkbench software, an ongoing project at The Australian National University, facilitates visualisation of, and numerical computation in, exact solutions to the Einstein field equation. Space-times, such as the Kerr black hole solution, are defined by the metric components as a function of position on one or more charts, together with the maps between the charts. GRworkbench is then able to perform numerical operations, such as integration of the geodesic equation, by automatically computing any required quantities which are dependent on the metric and its derivatives. Objects in four-dimensional space-times are visualised by projecting them under arbitrary transformations to a three-dimensional visualisation space, which is then viewable by the user from any position and angle.