window models open at the sides?

I found these awesome window models, but somehow they look strange from the sides, because they are open. Why is that so and whats the trick? I cant move them more inside the wall or the window pane starts to disappear.

Well that is, my friend, because they are open on the side!

They're meant to be used in clearly defined wall openings, surrounded by brushes, probably only ever seen from one side. With the "correct" use of the model, the sides of the window would not be seen, so the polygons are spared for performance reasons, resulting in the "open" look.

I wish someone would model me a frame around those two windows ^^ what a waste to map hundreds of frames around them

I solved it by adding a block around as a frame with a SKIP texture on the window pane side. looks great.