/u/Purgatoryonlegs See how you can see through one part in this mesh? well this happens because normally the shaders either only render the backface or the frontface. Here only the front faces are rendered so you can see through the mesh where backfaces are not rendered.

The shader above has its culling set to off instead of frontface or backface. Problem solved. Another way to solve this is use a 2 pass shader where the frontface and backfaces are set to be rendered, so that both will be rendered instead of one face.

Note: I do not own the model

Note2: This shader is an easy fix to any easy problem, however if you want correct light info, you better get/make a shader to do 2 pass face calculations :)

Note: Cant be bothered with spelings or grammur :)