Follow these practices for efficient processing of large surfaces.
Autodesk Civil 3D can build and store surfaces created from millions of points, but performance is often a problem for surfaces containing more than a few million points. Such surfaces require a long time to build, edit, and draw. This section describes several ways to work more effectively with large surfaces.
With large surfaces, avoid creating surface snapshots; instead, retain the active links to point files, XML files, or other input data. The drawback of a snapshot is that it uses system memory, so it can double the amount of memory required for the surface.
Snapshots are more useful with small surfaces. The presence of a snapshot results in faster surface rebuilds because Autodesk Civil 3D references the snapshot rather than redoing the operations that created it.