How may I apply material to the inside of a sphere?

Development Rendering
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1

I tried setting the normal to -1, but it didn’t work

2

You need to invert the normals of the mesh inside a 3d program.
Or if its bsp, make it hollow.

3

…what does “bsp, make it hollow” mean?
is it the german shortcut for the word: “beispielsweise” ?