Creo ModelCHECK > start_config_options > Custom Checks File
  
Custom Checks File
Specifies the name of the external text file in which custom checks are listed in the start configuration file. For example:
CUSTOM_CHECKS_FILE c:\apps\mc\config\text\custom_checks.txt
CUSTMTK_CHECKS_FILE text/custmtk_checks.txt
where custom_checks.txt is used to specify new checks created from two or more checks and custmtk_checks.txt is used to specify the custom checks created using Creo Parametric TOOLKIT.