Flashbang effect

Hi everyone. I asked one question, but I can not solve it in any way: how to realize the effect similar to the flashbang grenade (as in CS:GO). And I do not need a white flash, but a solidification of the image and its disappearance with time.

A similar question was asked at the forum 3 years ago, but there is still no answer. (Flashbang effect - Unreal Engine Forums)

Sorry for my english and thanks to Google translator!

You could put a scenecapture2d at the same place as the players camera, activate it for one frame when the flash bang goes off. Save this to a render target which you then put onto a widget over the players screen, then fade it out using an animation? There could be some way to make a material function to make a blur driven by some scalar parameter too?

Yes, I did so, but it does not work very well:

The picture obtained from scenecapture2d is superimposed with a post-process on the camera:

The scenecapture2d itself is attached to the camera on the character and completely repeats its position and parameters.
As you might guess, the black area is a picture with scenecapture2d. But the prospect is rather strange. How to deal with this?