How do you make a 3D Holographic Sight?

Complex but answerable question. I need others input on how to make a holographic sight with a model that can only be seen if you are looking through the sight. In other words, a REAL holographic sight. In more detail, a holographic sight is called holographic because it uses light reflected through glass to create a hologram that can be used for aim, but what is the point if it is 2D? A 2D holographic sight is just a glorified version of only 1 ironsight. You can't aim with it. Holographic sights are 3 dimensional, but can only be seen through the glass due to the way the glass projects the light.

Please, DO NOT tell me this isn't possible, because it is. I will say it again, don't tell me it is impossible. If you have nothing helpful to say, say nothing. Thank you.

Escape from Tarkov did it, and I am sure many others have as well.

The visibility of the sight is easy, if they are scaled-down parts then just make the transparency 1. Assuming you have the body of the gun made it will only take a little more welding to add the sight. For the visibility you would also need to detect when the aim button isn't being held down. The scaling can be done with a Model Scaling plugin to make it easier to design the sight as a whole because working with really small parts is a pain. I hoped this helped some.