A computer-implemented method of designing a dental restoration at a display includes providing a virtual three dimensional representation of at least a portion of the patient's dental situation. The method includes displaying a library arch form in an alignment with the virtual three dimensional representation of the portion of the patient's dentition. The library arch form includes a pair of two virtual library teeth packing to each other. The method also includes in response to a parametric change of one of the two virtual library teeth, moving the other virtual library tooth to keep packing to the changed virtual library tooth.