Large Triangulation surfaces, such as those built from DGM files, can require a substantial amount of memory (RAM and virtual memory) and disk space to build and save the surface. Triangulation surfaces require about 100 bytes per point, whereas grid surfaces require about 16 bytes per point.
It is important to ensure that you have sufficient resources before you build a surface using a DGM file. Also, be aware that certain commands may take longer than expected when working with these surfaces.
As a general rule, a 1 MB DGM file contains 160,000 points. For larger DGM files, the number of points grows proportionately to the DGM file size at a rate of approximately 160,000 points per 1 MB of DGM file size.