The teaching of 3D digital game design requires the development of students' meta-skills, from story creativity to 3D model construction, and even the visualization process in design thinking. The characteristics a good game designer should possess have been identified as including redesign things, creativity thinking and the ability to visualize ideas from imagination. Therefore, 3D visualization is a key skill in this context. To help students fully focus on game design rather than on complicated 3D modeling or animation skills, this study developed an authoring package that is integrated with Google 3D Warehouse, SketchUp, and a web-based 3D multi-user platform: 3D Cyber Worlds. The proposed game design authoring package was used with 53 college students for one semester, while a total of 108 students were involved in the overall study. The results indicate that the package achieved its aim of in assisting students in the game design process, including that of 3D modeling, and is feasible for future development using advance web technologies. Examples of the students' game design projects and feedback on the use of this authoring package are also presented and discussed.