Abstract: The present disclosure features methods and systems for managing concurrent design of computer-aided design objects or models. The systems include a common data model, comprising chapters of different information items to describe various aspects of the CAD model, and lightweight change instructions representative of modifications made by a user to a chapter of the CAD model. By utilizing a common data model and difference-based change instructions, a plurality of users may concurrently collaborate on the design of a CAD model, or a single user may utilize a plurality of applications of a CAD suite efficiently and with an enhanced user experience.