Chaos Corona Forum
Chaos Corona for Cinema 4D => [C4D] General Discussion => Topic started by: Shawn Astrom on 2017-12-19, 18:47:15
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Hey everyone, I just wanted to share a little tutorial I made with everyone here on the forums:
t=353s
Pretty cool little plugin: http://graphos.xyz/Products/
This is one way I figured out how to get https://refractiveindex.info/ into Corona.
Maybe there might be another way? Would love to see if any other Corona users have any ideas.
Thanks, people.
- Shawn
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Thanks Shawn - lots of good info here.
e.
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Hi,
As we discussed on you tube, here is my result on this subject using falloff, I put it all in diffuse channel just for visualisation purpose... Funny is that I have yesterday completed tutorial for my patreon page on this subject :)
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Awesome! Thanks so much, yeah I felt like the fresnel mapping was a bit off for sure...
- Shawn
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No problem, I had struggle with this also until I played with falloff where I found most simillar way to 3ds max falloff which is at the moment the only thing I miss in Cinema 4D...
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Thanks again for the tip! I made an updated tutorial using the Falloff shader!
Yeah it would be great if Cinema had a falloff shader with separate RGB channels!
- Shawn
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What I figured out is that the Falloff doesn't work as you expect it. It is not a falloff that looks at the view angle of the normal, it is more of a depth (if you use camera with z-direction).
Fresnel is the correct way to do it.
Set the gradient to linear and put the fresnel shader inside a filter and in there you can activate curves and voila, RGB channels can be set with that plugin or manually.
Don't flip the curves, you reverse the fresnel effect in that case.
Cheers...
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What I figured out is that the Falloff doesn't work as you expect it. It is not a falloff that looks at the view angle of the normal, it is more of a depth (if you use camera with z-direction).
Fresnel is the correct way to do it.
Set the gradient to linear and put the fresnel shader inside a filter and in there you can activate curves and voila, RGB channels can be set with that plugin or manually.
Don't flip the curves, you reverse the fresnel effect in that case.
Cheers...
Indeed, falloff in c4d =/= to the falloff in 3ds Max. Fresnel does seem to be better suited for the job.
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I'd also go with fresnel.
Since the fall-off shader takes the whole object into account, everything after 50% of the gradient won't be visible since it's going to be projected onto the objects back-side.(z-camera view)
However, it might be useful for non-opaque materials.
Edit: Since we're already on the topic of fancy materials, what about the thin-film shader?
I know it's mainly used for coatings, oil, iridescent mats etc. But could it play a role in this? Could it be abused instead of the fresnel shader to take the job?(given the right values&expressions)
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This is all great stuff and great ideas! I'm gonna have another play around and I might try and test these methods and compare them with other engines that have these features built-in. See if we can't come up with the "correct" way of doing this with Corona in C4D...
Maybe the developers can chime in as well on this topic? Do they plan on implementing this ability (without plugins) to have separate falloffs, facing ratio, Fresnel or whatever... for each color spectrum?
- Shawn
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I already talked about them about it and at the moment it is not in plans cause probably other stuff are more important, and as they said they need to make changes in corona core to make this happen. So I guess we will have to stick to these options we have atm :)
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Well for the most part this workflow is very specific and not a lot of users are going to go down this path... Even in 3ds Max you don't see that many people using this approach.
My guess is that there are other more fundamental things that are wrong in our renders than a perfect fresnel curve. Just guessing :) Its nice to see you guys are trying to mimick the workflow in c4d though! The more we get the better!
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Well, we are a bunch of people obsessed with details. ;)
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... or simply in love with reality & truth a.k.a. philosophers ;)
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Yeah, I just feel like there's certain gratification in knowing the correct way to do something and knowing that you have not made any mistakes. Also it's pretty cool to be able to look up scientific data and apply it to non-scientific art form :)
- Shawn
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@astrofalcon:
that is exactly what i posted here at post #4
https://forum.corona-renderer.com/index.php?topic=18552.0
;)
@Studio Heisenberg
that doesnt need changes in corona, i'm sure.
it just needs a simple shader and thats probably not priority
btw i think such a shader could be completely independent of the renderer