Based on the prior thread SMAA – Subpixel Morphological Antialiasing integration from 2016, I took a stab at getting SMAA integrated into the current version of the engine. Thank you, Leszek Godlewski, for a reference point to work from.
I’d tried turning it into a plugin, but the subpixel jitter for temporal AA’s doesn’t play nice with SMAA, so that effort became this Pull Request for ue5-main. Alternatively if you want to play with it now, my branch on GitHub should be accessible, but may not build.
I’ve probably broken the reference implementation a little as I found that the gbuffer world normal gives better edge masks than luminance or scene colour, so that’s the default for this implementation.