Application of LOD in collaborative design and information security

CAD models are required to transmit through network in many occasions, and the information security must be ensured. A transmission framework depending on progressive mesh is proposed in this paper. The description method level-of-detail (LOD) is introduced, which is a method to reduce the number of polygons for rendering, storage, transmission and following processing by using different-resolution details for the objects in a scene, while ensuring the image quality or geometrical accuracy. By using LOD structure tree, the model with the most appropriate resolution is transmitted automatically according to the bandwidth and the requirement of users. The data volume of transmission is reduced and the resolution is adjusted freely. Further more, by combining Christopher´s role-based viewing envelopes for information protection, the information security in collaborative design environment is ensured, and the leakage risk of important data is reduced in the muti-organization cooperation environment.