View dependent 3D-geometry streaming allows navigation of large virtual environments without requiring replication of the entire database at the client. We present scheduling policies for optimal transmission of multiple multiresolution 3D-geometry objects over congested network links. Using multiresolution objects allows smooth adaptation of the visual quality of the graphics environment with network bandwidth fluctuations. A greedy scheduling policy is used for minimizing the visual error received at the client. The performance is further increased using a look-ahead scheduling policy. Finally a scheduling policy using multicast transmission of 3D models is presented. The scheduling policy combines unicast and multicast transmissions in order to provide optimal visual quality of the virtual environment rendered at the client.