1. A computer-implemented method of automatically adding constraints between entities in a subject computer-aided design (CAD) model of a real-world object, the method comprising: storing information regarding CAD model entities and related constraints in a computer database, wherein the CAD model entities belong to one or more components of at least one of the subject CAD model and other CAD models; accessing the computer database to determine previously used constraints for at least one entity of a given component in the CAD model; and automatically adding constraints between at least one entity of the given component and another entity in the subject CAD model based on the previously used constraints.