Part of object disappears when viewed through a transparent material

Question

When using the Blender Game Engine, the parts of the model viewed through the windows becomes transparent and it's not a clipping problem. If I select a glass object the model viewed through the glass object shows up properly.

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I have tried both solidify and double sided and it doesn't help. If I select a transparent object, the object then shows the model through the object. When I press play, then everything works right. In the image I have selected the 'glass door' on the left and the object can now been seen, but not through the other windows. I hope this is alright to answer like this, as I don't see away to include an image in my comments.

Answer 1

My guess their normals are pointing to the opposite direction. One solution is to add a solidify modifier to it, or check in double sided in object data. The second option is maybe better for performance.