render target to static texture issue, looks 'sharpen', 'aliasing'.

[Santorrr]

Hello everyone,

I’m making a texture packer for project optimization in unreal engine.
To make this tool I use a ‘Material’ + ‘RenderTarget’.

Put textures to pack in material > Draw material to render target > Convert render target to static texture.

The result of the static texture looks ‘sharpen’, ‘aliasing’. I tried a lot of things to fix the problem but no success.

Render target is 16 bit per channel RGBA. (Same problem with 8 bit)
Static texture is 8 bit per channel RGBA.

I’m working with ue5.1.

If you have any idea to keep details and remove this “alias” effect.

Thanks you.

[RecourseDesign]

Hi Santorrr,

So is it simply a create rendertarget2d and drawmaterial - two node type thing? Can you share a snapshot?

One thing it looks a little like, is if “sRGB” was turned on when it shouldn’t be - don’t know if that will be the solution though…

[Santorrr]

Thank you for your answer,

I also developped few month ago a standalone tool to pack textures :

GitHub - santorr/TonyPacker

Then I tried to pack textures with this tool and import the result into UE5. The problem is still there.

I think it is more a source texture issue than a UE5 issue.

I also noticed that I don’t have this problem on every pack I made. This one is coming from quixel bridge.

I tried to manage sRGB as well as possible. Cause sometimes you want to pack textures that has sRGB or not. So I manage this in material. Everything looks okai on this side.

[RecourseDesign]

Yes packing channels is a great optimization.

It could be the source texture like you say - but one other thing you could try - I found I got some interesting image results if I created and used an HDR format with RTF_RGBA16 rendertarget - then at the last minute (just before saving) I change it to RGBA8 - I noticed Ryan Brucks’ did that in his Impostor Baker as well…

[Santorrr]

I tried fiew things that doesn’t work :
1 - Change the created render target to RTF RGBA16 and changed to RTF RGBA8 before genereate texture.
2 - Change the created render target to RTF RGBA16, create a texture with HDR16F compression, then change texture to RGBA8 before saving.

If I change the texture compression settings to ‘VectorDisplacement’ it looks like the imported texture … but the texture now make 5.5Mo instead of 0.7Mo, that’s not a great deal.

[Santorrr]

Okai to make my test (screenshot above) I downloaded surface textures (vl3lfddfw) from quixel bridge standalone app.
I downloaded each textures (Base color, normal, roughness, displacement …).
I did it from standalone app because I wanted to download each textures (the bridge in-app pack occlusion/roughness/displacement).

Just to make a test I had downloaded the same surface from in-app bridge. I also get the sharpen effect when I resize it with ‘Maximum texture size’ setting.

So yes that’s not my tool … It’s a texture issue.