meshes hollowing out in unity

[fullclipstudios]

i created a mesh in blender, and imported it, but in unity its showing up strange (only some of the meshes) with a weird hollow effect on the faces. see pics

unity:

blender:

[Kurt-Dekker]

Most Shaders / Materials in Unity only render one side of each triangle.

Here’s how to see which sides in Blender so you can flip them around: