To Trim a Mill Volume
Select the mill volume quilt that you want to trim and click > 
Trim. Alternatively, click > > Trim. Creo NC automatically subtracts the reference model from the current volume definition and only the remaining volume is used for machining.
Trim. Alternatively, click > > Trim. Creo NC automatically subtracts the reference model from the current volume definition and only the remaining volume is used for machining.To ensure that there is no gouging, Trim can also be used after offsetting all surfaces.