[Kevan]

This tutorial is very useful, when you have a 3D file that's too thin...or too thick you can modify it with the 'Displace' tool.

   

'Displace' adds or subtracts thickness, the default 'strength' is 1.000 which is 100% increase in thickness. 

0.000 'strength' would be no change, -0.100 would be 10% thinner and 0.100 would be 10% thicker.

   

Here's the Blender Thickening Tool Tutorial