Nonlinear Revision Control for Web-Based 3D Scene Editor

With the rapid development of web technologies, an increasing number of Web applications for 3D scene modeling have emerged. Over the Internet, 3D scenes can be easily shared and collaboratively edited. Concurrent editing on the same scene would bring conflicts, resulting with different versions, thus version control is needed. However, existing revision control systems focus more on text than binary file, which consumes a large amount of storage. We propose a nonlinear revision control mechanism for web-based 3D scene editor. In our system, 3D scene is represented and stored as a scene graph. Various algorithms are designed for revision control commands, such as commit, retrieve, branch, merge etc. To identify the discrepancies between two versions, we have introduced two kinds of difference, structure difference and state difference. With these differences identified, automatic branch merging can then be carried out. We have implemented the algorithms into a prototype system, which is built upon the TE, an open source web-based 3D scene editor.