Fresnel Ramp Procedural

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giannis
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Mon Jun 29, 2015 2:56 pm

Dear friends,

perhaps, some of you may remember the "fresnel ramp procedural" used in Kerkythea. That was a very interesting procedural, giving the ability for a broad material design approach.

In Thea Render context, when we started implementing the material system from scratch, we started too strict on what should be allowed and what not. In this context, we did not want to keep the "liberal" fresnel ramp procedural; instead we went for a more restrictive option, what we call the Fresnel curve - it is the user edited curve that can be seen in almost all material BSDFs. Although the Fresnel curve is the most physically-based strict approach, it is also restrictive with respect to what can be achieved with it.

As much as we like keeping the very strict, high end, characteristics of Thea, we also love seeing our users trying new things. In many ways, we have been surprised with the creations made either with Thea or Kerkythea. This is exactly why we have finally decided to carry over the awesomeness of Fresnel Ramp and not be so purists about it!

And here it is, Fresnel Ramp available for all engines. :)
Fresnel_Ramp_Satin.jpg
We didn't want though the new Fresnel Ramp to be a pure copy of the Kerkythea one. Instead, we added more ways of adjusting the reflectance, with more parameters and direct curve editing. It is even possible to create some psychedelic materials if one desires. Of course, the most ideal way to use the new procedural is probably for various cloth types; typically, where the reflective behaviour is flat at the center and raising near shallow angles.

Best wishes
Fresnel_Ramp_Jeans.jpg
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Mohammad Nael
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Mon Jun 29, 2015 4:01 pm

Nice feature :clap: , but will it stay in your computer :thumbdown: , where is the update :wtf: .
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Rombout
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Mon Jun 29, 2015 4:17 pm

Mohammad Nael wrote:Nice feature :clap: , but will it stay in your computer :thumbdown: , where is the update :wtf: .
hahahah Mohammad, really? your a beta :mrgreen:
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giannis
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Mon Jun 29, 2015 5:59 pm

I understand the anxiety :)

Yep, actually Rombout has access to this feature at the moment!? And would really love to see a render from Rombout using this feature, as I know he has used it in the past (with Kerktyhea) quite a few times. Not to mention the criticism why we left fresnel ramp "behind". :mrgreen:

Best wishes
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Pixero
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Mon Jun 29, 2015 7:17 pm

Thanks. It looks great.
I hope this is the first of several procedurals that will work with Presto.
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JQL
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Mon Jun 29, 2015 9:53 pm

I agree Pixero! I liked both this quoted parts:
giannis wrote:Dear friends,... available for all engines. :)
I also like the part were Kerky fresnel wasn't good enough... Thea had to have more... Now I can't stop wanting more and I'm specially awaiting a pimped up version of wireframe procedural, wich will allow us to add bevel/round edges... (available for all engines. :))

For what concerne fresnel procedural itself, I like the addition, of course, but I've been trying a while back, with the fresnel curve already existing in our matlab and it was capable of some convincing mats already... The artistic freedom here is welcome though!

Thanks Giannis!
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giannis
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Tue Jun 30, 2015 10:00 am

JQL wrote:Now I can't stop wanting more and I'm specially awaiting a pimped up version of wireframe procedural, wich will allow us to add bevel/round edges... (available for all engines. :))
This has given some boost in priority lately... My goal is to have the least possible but most effective procedurals for Presto. We are thinking for alternatives for the rest ones.
JQL wrote: For what concerne fresnel procedural itself, I like the addition, of course, but I've been trying a while back, with the fresnel curve already existing in our matlab and it was capable of some convincing mats already... The artistic freedom here is welcome though!
The way I see it now, is that the fresnel ramp is capable of more. Actually, this is the only "danger"... that it gives too much freedom for material creations. You can use the procedural in whichever component - diffuse, translucent, specular.

And you can go wild and make direct curve editing even in full RGB, like shown below. ;)
fresnel_ramp_rgb_curves.jpg
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JQL
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Tue Jun 30, 2015 10:06 am

I like it! Personally I don't think I'll use such creative freedom much. I don't want to do wicked things to my contractors. They have to be able build it after all...
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giannis
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Tue Jun 30, 2015 10:33 am

JQL wrote:They have to be able build it after all...
:lol:
No, that's definitely not necessary. You just stick with the Fresnel Ramp in the Ramp type and things will go much smoother. ;)
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Tue Jun 30, 2015 10:38 am

There's no such thing as a "smooth construction procedural" hidden somewhere in Thea or is there? That would definetely be handy for us architects!
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