| Description | Type | Default | 
|---|---|---|
|  
				   Defines the model units system for output labeling and report generation. The format is D-F-H-T where D is the distance specifier, F is the force specifier, H is the heat specifier, and T is the time specifier. The following options are permitted: 
  | 
 
				   D-F-H-T  | 
 
				   Undefined  |