Completing the Mesh
1. Continue modeling the surfaces.
Using the surfacing tools available to you, continue surfacing the model.
2. Using Align Mesh.
When you have a system of surfaces, it is difficult at time to get the surfaces to line up on all four sides of each surface. Alias has provided a tool for this called "Align Mesh".
To use this tools, pick Surface Edit -> Align Mesh -> options.
Reccommendations for using Align Mesh:
1. Save your file immediately before using Align Mesh. Alias has no undo for this function, you are on your own.
2. Turn "Keep Originals" off. Once you have the surfaces you want, picking the old surfaces to delete them can be a pain in some cases.
3. Try to be selective in the surfaces you align. I have found that if you use Align Mesh on just the surfaces you want, then align the remaining surface conditions using Object Edit -> Align, you can have more predictable results.
Theoretically, you should be able to select all of the surfaces you build, then apply "Align Mesh", and have brilliant results. Sometimes your model will not work this way. Please use the precautions above until you feel confident enough to use the tool the way it is theoretically supposed to work.
3. Complete the Mesh
Continue working your way around the model until you have finished the half of the model.