I’ve been working on a few prototypes and some of them use a weapon with a scope or binoculars. I’ve also just had a look at The Nest on Steam, which is ok but i’ve got a feeling these types of games will really look great if we could re-project the 3d matrix of the render target (It’d have to be done for each eye simultaneously though - which adds another layer of complexity). You’d just supply an offset from the ‘glass’ of the scope in x,y and z and you could really simulate looking down a lens rather than a 2d screen.
I’ve used off-axis projection in some earlier projects, but it was an engine mod rather than a plugin and it was for 4.8 i think. If there are any reasonable c++ coders here who might want to take a look you can find the thread in the answer hub.