To Create a Shell Feature
1. Click > 
Shell. The Shell tab opens.
Shell. The Shell tab opens.If the default body is a valid reference for the shell feature, a default thickness is applied to the inside of all the surfaces of the default body, creating a closed shell. The preview geometry is displayed.
2. To select the bodies from which geometry is removed, click the References tab and select an option:
◦ To shell geometry from all the bodies in the model, select All.
◦ To shell geometry from selected bodies:
1. Select Selected.
2. Click the body collector, and then select bodies from which to shell geometry.
3. To remove surfaces, on the References tab, click the Remove surfaces collector, and select one or more surfaces. You can also select the surfaces to remove before you enter the shell tool.
4. To modify the shell thickness, perform any of these actions:
◦ On the Shell tab, under Thickness, type a value in the box.
◦ Drag the thickness handle in the graphics window.
◦ Double-click the thickness value in the graphics window and type a new value.
5. To flip the shell inside or outside of the body, click 
on the Shell tab.
on the Shell tab.6. To define a different thickness for specific surfaces:
a. On the References tab, click the Non-default thickness collector, and select surfaces.
b. For each selected surface, define a new thickness value in any of these ways:
▪ Type a new value in the Non-default thickness collector.
▪ Drag the thickness handle in the graphics window.
▪ Double-click the thickness value in the graphics window and type a new value.
7. To exclude surfaces from being shelled, on the Options tab, click the Exclude surfaces collector, and select one or more surfaces to exclude from the shell.
8. Click 
OK.
OK.