Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Ahmad Kouti on 2021-03-04, 17:24:51
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Hi,
How to increase the accuracy of texture rendering when I using highly detailed textures.
For example, I used a brushed metal texture for my material, in a small size the details are lost.
How to increase the quality of the texture in a small size?
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What do you mean by increasing the quality? Do you have some examples of images you are struggling with?
Ultimately the details of your textures are limited by the number of pixels of your rendered image
If you are rendering at small resolutions you might as well be using 2k textures over 8k textures as by themselves it wont increase the quality of your final image.
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This is quite issue with texture filtering, none of the available filters in Bitmap and CoronaBitmap preserve details well unless you are rendering in really high-resolution (of framebuffer).
You can set most of your textures to "None" and 0.01, but this will create issues in many instances (particularly Normal and Bump mapping which require certain level of filtering). Other issue is that may just create artifacts (or just pure noise) instead of correct detail like when rendered up-close (or in high-res).
This is issue that makes many people, including me, very unhappy for many years and I don't think there is any solution right now outside of always rendering very high-res even if you down-sample afterwards for clients.
When you render 4x bigger (8k instead of 4k), you can use higher noise threshold since the noise will vanish after downsampling. So rendering higher-res doesn't necessarily mean higher-render time in linear fashion.
Your example (Anisotropic details of metal) are particularly the most glaring issue with this right now. With well filtered detail of texture, your metals would be perfectly brushed and anisotropic automatically, with no need for setting any roughness or anisotropy.
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Istnt it obvious that only high resolution will have enough pixels to show all those details. I dont get how it can be done by any other way.
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This is quite issue with texture filtering, none of the available filters in Bitmap and CoronaBitmap preserve details well unless you are rendering in really high-resolution (of framebuffer).
You can set most of your textures to "None" and 0.01, but this will create issues in many instances (particularly Normal and Bump mapping which require certain level of filtering). Other issue is that may just create artifacts (or just pure noise) instead of correct detail like when rendered up-close (or in high-res).
This is issue that makes many people, including me, very unhappy for many years and I don't think there is any solution right now outside of always rendering very high-res even if you down-sample afterwards for clients.
When you render 4x bigger (8k instead of 4k), you can use higher noise threshold since the noise will vanish after downsampling. So rendering higher-res doesn't necessarily mean higher-render time in linear fashion.
Your example (Anisotropic details of metal) are particularly the most glaring issue with this right now. With well filtered detail of texture, your metals would be perfectly brushed and anisotropic automatically, with no need for setting any roughness or anisotropy.
Thank you, very helpful
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What do you mean by increasing the quality? Do you have some examples of images you are struggling with?
Ultimately the details of your textures are limited by the number of pixels of your rendered image
If you are rendering at small resolutions you might as well be using 2k textures over 8k textures as by themselves it wont increase the quality of your final image.
Thanks
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Istnt it obvious that only high resolution will have enough pixels to show all those details. I dont get how it can be done by any other way.
Not really. Even if you apply a super high resolution image to a tiny detail in the scene, the features of the texture will be lost because of how the filtering works.
I think tech like this could help here:
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Istnt it obvious that only high resolution will have enough pixels to show all those details. I dont get how it can be done by any other way.
Not at all. Properties of materials can be shaded based on sub-pixel detail. That's already how it works right now, but not well enough when it comes to sampling that detail from bitmap textures.
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Damn guys, didnt know that. Very very interesting. Now I think I was better not being aware of this detail loss :D
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Not really. Even if you apply a super high resolution image to a tiny detail in the scene, the features of the texture will be lost because of how the filtering works.
I think tech like this could help here:
Yes please!!
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Damn guys, didnt know that. Very very interesting. Now I think I was better not being aware of this detail loss :D
World of CGI :D More you learn the more you become unhappy about your work. Endless struggle!
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I'd like to bring this up again to be considered for the list of new features/poll. Thanks.
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Istnt it obvious that only high resolution will have enough pixels to show all those details. I dont get how it can be done by any other way.
Not really. Even if you apply a super high resolution image to a tiny detail in the scene, the features of the texture will be lost because of how the filtering works.
I think tech like this could help here:
Jeez, no wonder I had such a hard time with glitter...
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I'd like to bring this up again to be considered for the list of new features/poll. Thanks.
This is one of the reasons I've been slowly transitioning away from Corona. Filtering/texture sharpness/resolution dependent bump mapping/DOF noise just isn't on point and I can't keep waiting for it to be fixed. I've been speaking about it for years.
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Curious to know wich renderer(-s) do you find works much better in this regard?
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FStorm. Specifically in the bump mapping/parallax bump department. Natural anisotropy can be achieved simply with micro fine bump mapping - and it doesn't change depending on the level of zoom/render resolution.
Filtering in general is always tack-sharp in FStorm: sharp, but without CGI'd jaggies on edges. Material bitmaps for some reason just seem more natural and less grainy - and I'm not talking about render noise, there's a kind of fine pixel noise in Corona that shows up that's hard to describe (which goes away with down sampling). I've mostly noticed it on wood materials - I did some side by side comparisons a while ago where it was very obvious (don't have them to hand).
Adding DOF also doesn't cause a massive performance hit/excessive noise (despite tweaked sampling balances in Corona). Being able to render out interior vignettes in 5 minutes vs 1 hour+ for a noise free DOF shot is nothing to sniff at.
I've transitioned all of my high-end product vis and 50% of interior work to FStorm, despite Corona being more feature rich and easy to use in places. Being able to render on 3x3090's is blazing fast, in comparison to my 3970x (no a 3990x wouldn't touch the speeds I can achieve in Fstorm on a single machine).
I'll always settle on whatever render engine suits my needs and use cases, so this isn't necessarily a knock on Corona as a rendering engine. If the above issues were sorted I would transition back in a heartbeat (while the FStorm dev is a coding wizard, I don't like his attitude at all).
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FStorm. Specifically in the bump mapping/parallax bump department. Natural anisotropy can be achieved simply with micro fine bump mapping - and it doesn't change depending on the level of zoom/render resolution.
But does it work with any arbitrary image, or just with Fstorm's native noise? I saw this feature praised many times, but it seems i can't get an answer to my question.
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But does it work with any arbitrary image, or just with Fstorm's native noise? I saw this feature praised many times, but it seems i can't get an answer to my question.
Yep, one of our use cases was mixing many 8K dirt maps, along with super stretched versions of the maps for beer can renders.