1. A vehicle package design system, comprising: a data store of vehicle packages defined in terms of spatial dimensions relating vehicle hard points; a design engine operable to visually render a vehicle space based on a vehicle package, wherein said design engine is operable, in response to user input defining a required change in a target spatial dimension, to alter the target spatial dimension according to the required change, and to alter at least one potentially altered spatial dimension of a plurality of potentially altered spatial dimensions based on alteration of the target spatial dimension; and a user interface having an output operable to communicate the plurality of potentially altered spatial dimensions to the user in a manner indicating them as potentially altered according to the alteration of the target spatial dimension.