SSS (poor funcionality) and Volumetrics have confusing parameters

[Mac3DX]

Hi Guys,

Let me put my thoughts here, and I would appreciate to be notified if I'm taking the wrong approach for that.

Once I'm coming from Modo, the simple SSS in Corona are very bad IMO. It seems not to respect the light distance you determine to scatter inside the geometry.

Please take a look at this image and observe the SSS effect chocolates usually have. Modo has a very fast and effective SSS and you can achieve good results and no time. No rocket science.



Here you can see how simple the parameters are in Modo. We have on the left just a difuse color and on the right the same color for the SSS material. Look how the SSS color is pretty close to the preview render.



Then, I tried to reproduce the same result with Corona. It doesn't produce the desired effect. Worse than that, the scatter color doesn't make sense to me. I don't see the color we set from it being reproduced.



Ok, so the solution is to use a more advanced property, which is Volumetrics, right? Again, it doesn't seem to do the job either. Mixing the absorption color with the scattering color, Jeez what a mess. The set colors make no sense to me. I really would like to understand the parameter relationship. I understand that Volumetrics works very well for materials with a lot of transparency and viscosity.

Conclusion, I can't get the desired result in a simple way. The appearance looks like too waxy and it's very annoying to find the desired color.

[Mac3DX]

I think the question is: How to get this level of control Vray offers? Being able to determine how hard or soft the material is. How the light passes through the object. What color that light would have. I don't know how to achieve this kind of control in Corona.

[burnin]

I'DK (TL;DR), but would consider fundamental differences between mentioned engines, then go about Volume vs. SSS... After, maybe add inverse AO or curvature shader or mix both... Finally, I'd just post a test scene here, as to show where I got stuck and issue gets fixed collectively for all our future endeavors  ;)

[Mac3DX]

Well, those simple examples are more than enough to show us we are missing core funcionalities. SSS materials are very complex and need some attention.

To start with, a fix for the color feedback would be a good start. Look at Vray how precise is the Fog color compared to the rendered image.

Corona principles are simplicity=realism. Considering Vray and Corona are from the same company, I see no reason to get equal results for both Render engines.

[burnin]

OK...

[John_Do]

SSS Works as expected here, you just have to fiddle a bit with several values to get the proper color but it's definitely possible and not rocket-science.

I just wish it was better sampled, currently it's very noisy against regular diffuse material, quite ugly.

[Mac3DX]

SSS Works as expected here, you just have to fiddle a bit with several values to get the proper color but it's definitely possible and not rocket-science.

I just wish it was better sampled, currently it's very noisy against regular diffuse material, quite ugly.

Thanks John_DO. Yes, very noisy and slow to render. Even Modo crap can be better in Render times for SSS.

I still think there is a lot to be improved in SSS, everything looks waxy IMO. Simple SSS in Corona is ridiculous. I don't see a purpose for use it. I'm exploring the Volumetrics feature yet, definitely I'll dig deep into that. it's a very important resource for organic materials and the most import part of my job.

[Mac3DX]

OK...

Simple SSS is rediculous! Make me laugh. It doesn't work for solid objects.

[Mac3DX]

SSS Works as expected here, you just have to fiddle a bit with several values to get the proper color but it's definitely possible and not rocket-science.

I just wish it was better sampled, currently it's very noisy against regular diffuse material, quite ugly.

Which version are you using, I see no camera/lights in your file.

[John_Do]

Which version are you using, I see no camera/lights in your file.

v8.
Because there are none, I was using a HDRI in an other scene, the file contains only the geo with materials.

[maru]

Maybe this can help?
https://support.chaos.com/hc/en-us/articles/4528339318289-What-are-the-two-available-SSS-modes-C4D

There is also this (pretty old) tutorial series which should cover all the SSS/volumetrics settings and the information in it should still be relevant in Corona 8 - https://youtu.be/a20emL2n9b8

IIRC there are also some chocolate material examples in the Corona Material Library.