Do .Tx files decrease 8k normal maps texture's quality?

[giandosopaolo]

Hi

I am rendering an animation where there is a fabric that uses a 8k normal map to increase the details.

I noticed that when I render the animation with the .tx version of the normal map the fabric surface details come out sort of blurred, like if the normal map texture had been downscale to 4k or 2k even. If I delete the .tx file and I render without it all the details come back in full strength.

Is this normal with 8k maps? Any way to avoid this problem?

[CiroCardoso3v]

Not sure what is the math behind, but Arnold will automatically select the best resolution based on the distance. If you download this EXR file, you can see that in action.

https://dgruwier.gumroad.com/l/LJehG

I guess the solution would be to delete the TX file for that bitmap.

[n_rehberg]

You can force Arnold to use higher res mip map levels by using the Mip-Map Bias attribute on the file node. Try -1 or -2 and see if that helps.

https://docs.arnoldrenderer.com/display/A5AFMUG/Mip-Mapping+Bias

[giandosopaolo]

I tried that  @n_rehberg it does not work unfortunately.

[giandosopaolo]

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@CiroCardoso3v wrote:

Not sure what is the math behind, but Arnold will automatically select the best resolution based on the distance. If you download this EXR file, you can see that in action.

https://dgruwier.gumroad.com/l/LJehG

I guess the solution would be to delete the TX file for that bitmap.

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I downloaded and tried the tester exr but it does not show 8k.

Yes deleting the TX file map works but I wonder why 🙂

I actually thought Arnold could not render without these TX files.

[thiago.ize]

Arnold can render without .tx files. The issue is that these other image formats can consume way more memory in Arnold and if you have lots of non-tx textures, you can end up exceeding your texture cache and performance plummets.

I'm surprised that adjusting the mipmap bias on the texture didn't help. What if you do something really large like -10? Can you do that with the tester exr mentioned above to see if it at least gets you a higher res level (probably need to plug that into the diffuse color slot so you can see it)? If large bias isn't working, then there's either a bug in arnold or it's not being set properly on your end. Images showing what you're trying would go a long ways towards helping us know where the problem might lie.