When files containing Mechanical APDL-related data are large, loading them into the program or writing them out to an external file can be a slow process. For example, consider a problem file which contains nearly 462,000 lines, 150,000 of which contain nodal data and 97,383 of them containing data for elements. Because many of the lines in this file are in command format, Mechanical APDL requires much time to read it.

You can shorten the time the program requires to read such files by including two commands in your programs, UPFs, or macros: EBLOCK and NBLOCK. The NBLOCK command converts nodal data into fixed format data blocks (which Mechanical APDL can read more quickly than commands). The EBLOCK command places element data into a fixed format block, one line per element. These commands also compress displacement constraint data to one line per constraint node. See The CDWRITE (CDB) File Format in the Guide to Interfacing with Mechanical APDL for more information on the use of these commands.