Model-Based Definition > Model-Based Definition > Working with Model Properties > Units > About Measurement Units
About Measurement Units
Each model has a basic system of metric and nonmetric units to ensure that all material properties of that model are consistently measured and defined. All Creo Parametric models have length, mass/force, time, and temperature units defined.
Creo Parametric comes with some predefined systems of units, one of which is a default system of units. You can change the assigned system of units, and you can define your own units and systems of units (called custom units and custom systems of units). You cannot change the predefined systems of units.
Use the Units command to set, create, change, review, or delete a system of units or a custom unit for your model.
When you use the Units command, the Units Manager dialog box opens. This dialog box lists the predefined systems of units and any already defined custom systems of units. Using this dialog box, you can create new custom units and systems of units. A red arrow indicates the current system of units for the model.
Use custom units only if your model does not contain standard SI or British units or if your Material file (which you set up by using the Material command under Edit > Setup) contains units that cannot be derived from the system of units or both. Creo Parametric uses the definition of a custom unit in interpreting material properties. You can also use custom units to create a new system of units.
* Although the configuration options pro_unit_length and pro_unit_mass are still available, they are no longer recommended for use. It is recommended that you create a template for models that has a fully defined system of units. Use File > New, clear Use default template in the New dialog box, and then use the New File Options dialog box to create a template or modify one of the PTC standard templates. In any case, you must make sure that you have a defined set of units before you design your model.