1. A method of managing concurrent design of computer-aided design (CAD) objects or models, comprising: storing, by a first CAD application executed by a processor of a computing device, a starting state of a CAD model; modifying, by a user of the first CAD application, the CAD model; creating, by the first CAD application and responsive to the modification, a first one or more change instructions representative of the user's modification to the CAD model; loading, by a second CAD application executed by the processor of the computing device, the stored starting state of the CAD model and the first one or more change instructions; and executing, by the second CAD application, the first one or more change instructions to reproduce the user's modification to the CAD model.