The disclosure notably relates to a computer-implemented method for designing a three-dimensional (3D) model. The method includes obtaining a first 3D model, the first 3D model being defined by: (i) one delegated data object comprising input parameters specific to a type of the delegated data object and (ii) an output topology, and being associated with a sequence of geometric design operations. The method also includes performing, by a user, a first geometric design operation on the first 3D model, thereby obtaining a second 3D model, determining whether the output topology of the second 3D model can be retrieved from the output topology of the first 3D model, replacing the first delegated data object by a second delegated data object if the output topology of the second 3D model cannot be retrieved from the output topology of the first 3D model or keeping the first delegated data object and storing the first geometric design operation with the sequence of geometric design operations associated the first 3D model.