The Prep File is a format is used by Prep, SoilMesh, Submodeler, and SASSI User Interface. The Prep file is stored in an ACSII format. The file contains one or more commands that will be processed in a batch style until the end of file is reached. The file is usually denoted by the *.pre extension but this extension is not required for the file to run properly. The file is loaded by the Input Command or by appropriate menu option for the user interface being used. The Write command is used to generate most prep files but a user can create or modify a prep file in other ways.
When the Prep file is loaded into one of the user interfaces it will start executing commands that are in the file until the end of file is reached. The commands will have the same effect as if the user entered the commands by hand. Loading a Prep file does not delete and model data in the user interfaces memory unless commands in the Prep file specifically delete data. This can allow the user to maintain a single file for prep model geometry and just change the materials by loading a second prep file. However, it can create corrupted models in the interface memory if the user is not careful to properly clean the interface memory when working on unrelated models.
Since the Prep file is a command batch. The user may add or remove commands in a text editor such as notepad or as long as the file is save as an unformatted text file (*.txt equivalent). The user is limited to entering one command per line. If a command is invalid the user interface will simply report the error for that command and continue to process the rest of the file.