the constraint generator 32 heuristically determines the constraints imposed on the model by the designer for example if the constraint generator 32 observes that in the translated object 203 two surfaces are separated by a gap that is very small compared to the overall dimensions of the structure the constraint generator 32 will assume that an error has been made in translation and that the two surfaces are meant to be joined the constraint generator 32 then transmits a signal containing constraint information 206 to a model enhancer 34 that incorporates this information into the translated object 203 the model enhancer 34 incorporates the constraint information 206 by generating a hybrid object 204 in which the translated object 203 is augmented by information about relationships that must be satisfied between the various constituents of the structure these relationships which are collectively referred to as constraint information 206 can either be generated heuristically by the constraint generator 32 as described above or they can be provided directly by the user the resulting hybrid object 204 thus contains two distinct portions a geometry portion obtained directly from the translated object 203 output by the translator array 24 and a constraint portion obtained from the constraint generator 32 and combined with the geometry portion by the model enhancer 34 in the preferred embodiment the constraint information 206 take the form of constraints that are to be satisfied at the boundaries between the various constituents of the structure examples of such constraints are that two surfaces are continuous at their boundary that two surfaces are tangent at their boundary or that two surfaces intersect at a specified angle however the constraints can be far.