Is there a way I can see how the clear coat node works in the back?

Discussion related to the LuxCore functionality, implementations and API.
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TStrolia
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Joined: Mon Jun 22, 2020 10:29 am

Is there a way I can see how the clear coat node works in the back?

Post by TStrolia » Mon Jun 22, 2020 10:40 am

Of course there is. I downloaded the source but there’s a lot to dig through and I have found the UI files for the nodes but specifically I am trying to see the math of how luxcore is handling the absorption effect. Long story short I like it and want to see the math of how it’s handling it and use it to experiment a bit. Is there a specific file path(s) for the functions handling glossy and clear coat absorption? I’ve used luxrender long enough that I know what the effect looks like but I’ve been building complex node groups for some years now and I’d like to better understand how lux is doing it.

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Dade
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Re: Is there a way I can see how the clear coat node works in the back?

Post by Dade » Mon Jun 22, 2020 10:48 am

Are you talking of the GlossyCoating material ? I don't remember how exactly it is exposed in Blender (it may be an option flag and not an explicit node). The C++ source is here: https://github.com/LuxCoreRender/LuxCor ... oating.cpp

Or clear coating of Disney material ? It is here: https://github.com/LuxCoreRender/LuxCor ... disney.cpp (at this line: https://github.com/LuxCoreRender/LuxCor ... y.cpp#L218)
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TStrolia
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Joined: Mon Jun 22, 2020 10:29 am

Re: Is there a way I can see how the clear coat node works in the back?

Post by TStrolia » Thu Jun 25, 2020 5:12 am

Dade wrote:
Mon Jun 22, 2020 10:48 am
Are you talking of the GlossyCoating material ? I don't remember how exactly it is exposed in Blender (it may be an option flag and not an explicit node). The C++ source is here: https://github.com/LuxCoreRender/LuxCor ... oating.cpp

Or clear coating of Disney material ? It is here: https://github.com/LuxCoreRender/LuxCor ... disney.cpp (at this line: https://github.com/LuxCoreRender/LuxCor ... y.cpp#L218)
Thank you. Definitely the prior and not the latter. My main issue is actually because of the disney shader. It drops conservation of energy so I am experimenting in lux, cycles, arnold, etc, and trying to figure out what is going on with everything to try and better understand how to build a coating that will honor light conservation. I looked at the code and following some of it gets a little tricky just because its in C and well, I am not proficient in C. TBH I am not proficient in much outside of a handful of web languages. I was able to understand a bit of it. Luxrender, solely from a visual standpoint handles glossy coating much better in my opinion. I don't know the accuracy of it from a scientific point of view until I understand the node better but visually it looks closer to what I would expect. Arnold does a good job too, and although I no longer have access to thea I am sure they do just fine. Cycles is atrocious with clear coats and so is render man in my opinion. I would like to get a better idea of whats going mathimatically in luxrender, or lux core (been a long time since I have used anything other than arnold or IRay. Last I was here it was called luxrender.) in hopes to have a better understanding of how to deal with different conservation issues in various different engines, lux included.

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