Fundamentals > User Interface Basics > Customizing the User Interface > Entity Display > To Show or Remove Hidden Lines
  
To Show or Remove Hidden Lines
Click on the Quick Access toolbar. Click one of the following buttons on the list.
Hidden Line—Hidden lines are displayed in gray. The toolbar button shows dotted lines for clarity.
No Hidden—Hidden lines are removed.
or
1. Click File > Options > Entity Display.
2. Under Geometry display settings, in the default geometry display list click Hidden Line or No Hidden Line.
3. Click OK in the Creo Parametric Options dialog box. A message is displayed.
4. In the message box, click No to apply the settings to the current session only.
Click Yes if you want to save the settings to a config.pro file for using later in another session.