MOUS_ICO Menu: Noise > Hard ground regions > Passive
or
MOUS_ICO Menu: Noise > Hard ground regions > Dialog box…MOUS_ICO Select one or several hard ground regions in the listMOUS_ICO Dialog box: Passive
nco: Select a hard ground regionMOUS_ICO Popup menu: Passive
Sets the selected hard ground regions passive. Passive hard ground regions are not included in noise calculations.