1. A method for generating a computer representation of a three-dimensional (3D) swept envelope of a vehicle having a wheeled chassis operable to support a vehicle body for movement along a terrain, the method comprising: receiving terrain data providing a 3D representation of a terrain; receiving data defining parameters of the vehicle; receiving data defining a path for movement of the vehicle from an initial position on the terrain to a displaced position on the terrain; disposing a computer representation of the vehicle on the 3D representation of the terrain at successive locations along said path using said parameters, wherein said disposing comprises: determining points of engagement between a computer representation of wheels of the wheeled chassis and the 3D representation of the terrain to dispose the chassis with respect to the terrain; and determining a corresponding 3D location of the vehicle body with respect to the terrain; and generating a plurality of spatial extents of the vehicle at said successive locations, said spatial extents defining the 3D swept envelope of the vehicle when moving between said initial position and said displaced position.