Edit Shell Pair Definition
To edit a shell pair, right click the shell pair on the Model Tree and select Edit Definition. Creo Simulate opens the Shell Pair Definition dialog box. While editing the shell pair definition, the References section of the dialog box has options that are different than the options available when creating a new shell pair. The following options are shown in the References section:
• Top Surface(s)—The collector displays the current top surface or surfaces. Select this collector and click the new surface you want to designate as the top surface in the shell pair.
• Bottom Surface(s)—The collector displays the current bottom surface or surfaces. Click this collector to activate it and select the new surface you want to designate as the bottom surface in the shell pair.
• 
—Click the (Flip Top and Bottom Sides) button to interchange the top and bottom surfaces in the shell pair. This results in reversing the direction of the resulting mesh normal.
—Click the (Flip Top and Bottom Sides) button to interchange the top and bottom surfaces in the shell pair. This results in reversing the direction of the resulting mesh normal.The 
button is not available during edit.
button is not available during edit.