Disclosed is a parametric feature-based 3D CAD system that allows multiple users to simultaneously edit a parametric feature-based 3D CAD model consisting of 3D parts and assemblies of those parts (3D Model). Several CAD users, each using their own computer, phone, or tablet, can edit the same 3D Model at the same time. Editing may be separate and simultaneous—there is no need for users to worry about locking, checking out, or otherwise restricting each other's access to 3D Models. As a result, users see each other's changes occur in real-time, and may also identify what aspects other users are actively modifying through visible Collaboration Cues.