Command entry: 
Modify panel

Make a selection.

Modifier List

Object-Space Modifiers

Push
Command entry:Make a selection.

Modifiers menu

Parametric Deformers

Push
The Push modifier lets you "push" object vertices outward or inward along the average vertex normals. This produces an "inflation"
effect that you can't otherwise obtain.
Interface
- Push Value
-
Sets the distance in world units by which vertices are moved with respect to the object center. Use a positive value to move
vertices outward, or a negative value to move vertices inward.