Assign Buoyant Air Material
Hide the outer casing.
Select the internal air.
Open the Materials quick edit dialog in ONE of the following ways:
- Click Edit from the toolbar:
- Click Edit from the Materials context panel:
On the Material quick edit dialog, Type = Fluid
Name = Air
To allow the properties to vary with temperature, click Set... on the Environment line. On the Material Environment dialog, select Variable, and click OK.
Click Apply.