A system for collaborative three-dimensional (3D) modeling in a browser application is stored as instructions on a computer-readable medium. The instructions include a browser interface module that executes on the one or more processors to receive user commands from the browser application for modifying a 3D model and cause a rendering of the 3D model to be displayed in a window controlled by the browser application. The instructions further include a modeling engine module that executes on the one or more processors to interpret model data corresponding to the 3D model to generate the rendering of the 3D model, and modify the model data in accordance with the received user commands. Still further, the instructions include a collaboration module that executes on the one or more processors to cause the modified 3D model to be synchronized in real time.