Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Hadi on 2018-11-27, 22:24:14
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Hey guys,
I've been testing some new 3d scans with the guys at Poliigon these days and we can't replicate the quality of the details visible with Blender and Cycle in Corona.
Basically, main issue is the fact that the diffuse map is losing those small little details visible in their demo render, other than looking a lot more rubbery/glossy than the way more realistic one done in Cycle.
I've attached some screenshots for you to have a look at. Let me know if you need more info.
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Any chance of sharing the material set ups? A look at the renders doesn't look to me like a difference in the Diffuse channel, but in the Glossiness, Fresnel, or some other reflectivity attribute. Could simply be a case of the material not being converted properly, rather than any inherent loss of detail in a map.
EDIT - I am not sure what the third image shows, so can't comment on that :) Just looking at the "looks more rubbery" and the clear differences in reflectivity between the two renders.
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Hey Tom,
The third image is to show the small details in the diffuse map that are disappearing at render time.
I will speak with the guys at poliigon to ask them if it's possible to share the model with you.
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Tom, I had a reply from the Poliigon team who did some further test dropping the IOR value. You can see the result in the attached screenshots.
i think thought than an 1.1 IOR is incorrect as, according to the PBR workflow, the reflections should be fully white, without a map in the reflection slot and a 1.52 IOR.
Let me know your thoughts about it.
Thanks.
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if you in 3ds max try to reduce blur filtering in bitmap loader
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Ok, I think I've nailed it down and I'm reporting here in case someone is interested.
You can check the screenshot, but I think the result is quite close to the demo render from Poliigon, and I've just used a studio setup.
So, IOR 1.52, PBR mode on but with the reflection map in the slot, toned down by 50% of the one Poliigon provides with the model. I know that's not the correct approach, but I'm having a way better result with the map on. I'm open to suggestion if I'm doing something wrong.
Normal map bumped to 2.5 with the flip green ticked on.
Reducing blur filtering didn't change anything.
Reflection and glossiness maps have been loaded with the automatic mode, but I would like to have your opinion if this is wrong and I should load them with a 1.0 override.
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Ok, I think I've nailed it down and I'm reporting here in case someone is interested.
You can check the screenshot, but I think the result is quite close to the demo render from Poliigon, and I've just used a studio setup.
So, IOR 1.52, PBR mode on but with the reflection map in the slot, toned down by 50% of the one Poliigon provides with the model. I know that's not the correct approach, but I'm having a way better result with the map on. I'm open to suggestion if I'm doing something wrong.
Normal map bumped to 2.5 with the flip green ticked on.
Reducing blur filtering didn't change anything.
Reflection and glossiness maps have been loaded with the automatic mode, but I would like to have your opinion if this is wrong and I should load them with a 1.0 override.
Can you show a material graph for your approach?
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Ok, I think I've nailed it down and I'm reporting here in case someone is interested.
You can check the screenshot, but I think the result is quite close to the demo render from Poliigon, and I've just used a studio setup.
So, IOR 1.52, PBR mode on but with the reflection map in the slot, toned down by 50% of the one Poliigon provides with the model. I know that's not the correct approach, but I'm having a way better result with the map on. I'm open to suggestion if I'm doing something wrong.
Normal map bumped to 2.5 with the flip green ticked on.
Reducing blur filtering didn't change anything.
Reflection and glossiness maps have been loaded with the automatic mode, but I would like to have your opinion if this is wrong and I should load them with a 1.0 override.
Can you show a material graph for your approach?
There you go.
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Nothing seems off apart from the bump being at 2.5.
I wonder if this is anything to do with the way corona samples bump maps and doesnt do microgeometry well.
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Nothing seems off apart from the bump being at 2.5.
I wonder if this is anything to do with the way corona samples bump maps and doesnt do microgeometry well.
It does not. Normal maps should almost always be set to 1.0 strength and Corona has no problem with that.
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I wonder if this is anything to do with the way corona samples bump maps and doesnt do microgeometry well.
It does not. Normal maps should almost always be set to 1.0 strength and Corona has no problem with that.
My bad i just noticed its a normal not a bump
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Nothing seems off apart from the bump being at 2.5.
I wonder if this is anything to do with the way corona samples bump maps and doesnt do microgeometry well.
It does not. Normal maps should almost always be set to 1.0 strength and Corona has no problem with that.
At the end of the day what matters is how it looks. So if breaking the rule makes it look better, I would use a 10 multiplier.
I actually had to do that in order to make the bump pop out from another model of theirs (the blueberries), so I'm not really against on breaking the rules when necessary.
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If you have to greatly exaggerate normals just for model to look right, that might mean there's still something wrong with your setup, or with textures.
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If you have to greatly exaggerate normals just for model to look right, that might mean there's still something wrong with your setup, or with textures.
There's definitely something wrong with the textures that came out from the 3d scan, as I had to manually correct all of them (refl, gloss and normals).
As I said before, I had to boost 10 times the normal map in the blueberries in order to get the details out of the normal map.
I am not sure if the original one rendered in Cycle was actually looking correct without any map being corrected.
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
I've been using their textures since a while now and never had trouble, that's not the subject of the topic.
What we are discussing here are the 3d models, that are basically a new feature they introduced.
The suggestion to decrease drastically the IOR to 1.1 and boost the normal to 2.0 came straight from their end, meaning the standard material setup is not behaving in a canonical way.
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
I've been using their textures since a while now and never had trouble, that's not the subject of the topic.
What we are discussing here are the 3d models, that are basically a new feature they introduced.
The suggestion to decrease drastically the IOR to 1.1 and boost the normal to 2.0 came straight from their end, meaning the standard material setup is not behaving in a canonical way.
Id say its less a corona problem then and more a problem with their 'PBR' workflow. If they made their normals correctly it shouldnt need to be above 1 as was already mentioned. That data should be encoded into the map.
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
I've been using their textures since a while now and never had trouble, that's not the subject of the topic.
What we are discussing here are the 3d models, that are basically a new feature they introduced.
The suggestion to decrease drastically the IOR to 1.1 and boost the normal to 2.0 came straight from their end, meaning the standard material setup is not behaving in a canonical way.
Id say its less a corona problem then and more a problem with their 'PBR' workflow. If they made their normals correctly it shouldnt need to be above 1 as was already mentioned. That data should be encoded into the map.
Yeah I agree with you, that was my point.
I think at the moment there's no other way than re-do Corona materials for all of them, until they will fix it.
I appreciate they are providing materials for the most important softwares and render engines, so it's quite of a big commitment.
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
I've been using their textures since a while now and never had trouble, that's not the subject of the topic.
What we are discussing here are the 3d models, that are basically a new feature they introduced.
The suggestion to decrease drastically the IOR to 1.1 and boost the normal to 2.0 came straight from their end, meaning the standard material setup is not behaving in a canonical way.
Id say its less a corona problem then and more a problem with their 'PBR' workflow. If they made their normals correctly it shouldnt need to be above 1 as was already mentioned. That data should be encoded into the map.
Yeah I agree with you, that was my point.
I think at the moment there's no other way than re-do Corona materials for all of them, until they will fix it.
I appreciate they are providing materials for the most important softwares and render engines, so it's quite of a big commitment.
Out of curiosity have you tried with any other engine?
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They don't have scanned models free sample, so i downloaded this texture (https://www.poliigon.com/texture/ground-tire-tracks-001), which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot
I've been using their textures since a while now and never had trouble, that's not the subject of the topic.
What we are discussing here are the 3d models, that are basically a new feature they introduced.
The suggestion to decrease drastically the IOR to 1.1 and boost the normal to 2.0 came straight from their end, meaning the standard material setup is not behaving in a canonical way.
Id say its less a corona problem then and more a problem with their 'PBR' workflow. If they made their normals correctly it shouldnt need to be above 1 as was already mentioned. That data should be encoded into the map.
Yeah I agree with you, that was my point.
I think at the moment there's no other way than re-do Corona materials for all of them, until they will fix it.
I appreciate they are providing materials for the most important softwares and render engines, so it's quite of a big commitment.
Out of curiosity have you tried with any other engine?
With VRay. Same issues.
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Definitely poor PBR implementation (or understanding) from their part. Their preview thus look good with highly decreased specularity, but it will only look good isolated and from certain angle, light direction.
I would do what Romullus suggested. When the original preview is authored in poor way, you can always get good result by tweaking the shader yourself, you just can't plug&play without effort.
BTW, one thing regarding gamma for glosiness/roughness maps. There isn't actually agreed way that these should be linear/1.0. Logically they should, and it's also how they are read by default in Unreal for exanoke, but this depends on how they were created/authored. So sometimes you need to try both gamma when loading the bitmap to see which one they actually authored it for. Or just use CC node.
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Definitely poor PBR implementation (or understanding) from their part. Their preview thus look good with highly decreased specularity, but it will only look good isolated and from certain angle, light direction.
I would do what Romullus suggested. When the original preview is authored in poor way, you can always get good result by tweaking the shader yourself, you just can't plug&play without effort.
BTW, one thing regarding gamma for glosiness/roughness maps. There isn't actually agreed way that these should be linear/1.0. Logically they should, and it's also how they are read by default in Unreal for exanoke, but this depends on how they were created/authored. So sometimes you need to try both gamma when loading the bitmap to see which one they actually authored it for. Or just use CC node.
That's the only one way at the moment unfortunately, I'm merging their objects in a studio set up and tweak maps and shaders until I get the proper look.
That's something I do with all the 3d assets from libraries anyway, it's unlikely you will get something perfectly working without touching anything.
I thought this wasn't the case with their models though, as they advertised it as a no-hassle one click merging for several render engines.