Creo Options Modeler > References > Fundamentals > Creo Parametric User Interface > The File Menu > Opening Files > About Previewing Files
  
About Previewing Files
Use Preview in the File Open (File > Open ) dialog box to preview parts, drawings, and assemblies before opening them or to search for a file if you do not know the file name. Previewing while browsing is convenient when you must open a Creo Parametric object file to incorporate into a design, for example, or when you must specify a component to assemble.
 
Previewing is available for files saved in a version of Creo Parametric that supports previewing.
Objects appear in the Preview window as they were saved. For example, if the layer for datum curves was blanked when the file was saved, that layer is blanked in the preview.