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General Questions

Hello all. I’m just giving some of the editors more detailed features a once over and I want to ask some noobish questions.

Firstly, antialiasing. In the project settings, under rendering, there is an option to choose between Temporal AA and FXAA. Looking for the first option online tells me that it seems to be an Nvidia technique. I take it this means it doesn’t run very well with AMD? This is a shame, because the image results show it is vastly superior to FXAA. Can anyone tell me how well it works with AMD cards?

Lastly, ambient occlusion, something I know very little about. When playing around with the editor, I notice that AO is being collected in the corners of the room I have set up. I always thought that AO was something that had to be baked. How is UE4 creating AO at runtime? Is it very high in render cost? Does it mean that I don’t have to bake out AO maps for high-poly meshes with normal maps and such? And how do I switch it off and on?

Thanks in advance for any answers. :slight_smile:

Epic’s implementation of TXAA is their own and not Nvidia specific. There’s been tons of implementations of Temporal AA in games and game engines, and it’s naming varies. AMD cards do not have a disadvantage when using TXAA.

The default AO is screen space which is a 2d post process effect. It can be turned off in the post processing volume settings. The render costs are pretty low for the standard implementation. You can bake AO with lightmass, or try to use alternative AO methods.

Thank you kindly ZacD.

Can you explain ambient occlusion further? What is the point of AO maps if I can just use SSAO?

AO maps are baked in and wont work on dynamics objects, what i mean by that is that they wont update in real time when objects move apart of closer to another, SSAO is a cheap method of faking that. in most games it works fine but if you have delicate visuals perhaps you would consider turning it off as it is a post process effect and can produce edge artifacts and dark halos in some cases and may get the image “muddy”, but this is a rare case scenario depending on visuals, for most of the stuff out there it should be fine, plus you can control it from the post process volume.

Got it, thanks again. Another question: is it possible to set an option in a game to switch over from FXAA to Temporal AA?