1. A tangible non-transitory computer-readable medium storing instructions for collaborative three-dimensional (3D) modeling in a browser application that executes on one or more processors of a first computing device, the instructions comprising: 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; 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; and a collaboration module that executes on the one or more processors to cause the modified 3D model to be synchronized in real time between the first computing and a second computing device at which the 3D model is being concurrently developed, wherein the first computing device and the second computing device operate independently of each other on a communication network.