A process for the generation of a computer image of a coated, three-dimensional object involves applying at least a relevant coating layer on at least two test panels under the influence of a set of coating parameters which differs with respect to each panel; taking a plurality of measurements of at least one optical surface property as a function of the set of coating parameters selected on application of the relevant coating layer on each panel; storing the optical data in a datafile with assignment of the relevant set of coating parameters; facetting the visible surface(s) of a three-dimensional object by computer into a sufficient number of flat polygonal areas each being sufficiently small for the sufficiently accurate description of the surface topography; assigning the relevant set of coating parameters and associated optical data in each case to each individual polygonal area by computer; and assembling the polygonal areas into a computer image of the three-dimensional object.