Weird invisible faces problem?

Ok i am making some models for my game so i made this starbase (obviously not finished yet)
It looks like this:

the little donout shaped parts of the starbase (which is the part that is having problems) i made by creating a circle and then just spinning it around the center 360 degrees.

For some reason in panda it ends up like this:

Does anyone know what im doing wrong :question: :question:

Your model is inside-out. This is a common problem. You need to reverse the normals and/or the face winding order. I think there are some forum threads describing how to do this in Blender.

David

ok i wondered about this thanks