Creo Simulate > Additional Information > Units > Set the Principal System of Units
  
Set the Principal System of Units
Use the Set button on the Systems of Units tab to set a system of units as the principal system of units for your model. When you select a system of units from the list and click the Set button, a dialog box opens.
Select one of the following options in the dialog box:
Convert dimensions (for example, 1" becomes 25.4mm)
Select this option if you change your system of units after you design your model. Creo Parametric converts your existing Creo Parametric or Creo Simulate data to the new system of units but does not change the physical size of your model.
Creo Parametric converts the following values for your model:
geometric dimensions
materials
loads
prescribed displacements
idealizations (mass, springs, beams)
properties (beam section, beam orientation, spring properties, mass properties)
Creo Simulate design variables based on Creo Parametric dimensions or beam sections
in a global sensitivity study, start and end values of Creo Simulate design variables based on Creo Parametric dimensions or beam section dimensions
in an optimization study, minimum and maximum values of Creo Simulate design variables based on Creo Parametric dimensions or beam section dimensions
Creo Parametric does not convert design variables based on Creo Parametric parameters.
Interpret dimensions (for example, 1" becomes 1mm)
Select this option if your model has correct values but an undesired system of units. Creo Parametric does not convert existing Creo Parametric or Creo Simulate data to the new system of units. Creo Parametric changes the physical size of your model but not your model's dimensional values.
When you click OK in the Warning message box, Creo Parametric sets the selected system of units as the principal system of units for your model.
Angular units are not affected by either of these options.
Return to Systems of Units Management