Author Topic: How to increase SSS effect over 100%  (Read 2423 times)

2022-06-05, 20:23:29

Mac3DX

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Hi,
Playing around with SSS to get closer to the reference, but it seems SSS in Corona doesn't offer to much control straight out of the box.
The effect is to weak and we should be able to go further than the 100% in order to achieve a more real visual representation.
Any idea how to do that?

« Last Edit: 2022-06-07, 22:33:33 by Mac3DX »

2022-06-06, 08:03:15
Reply #1

TomG

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I'd try increasing the radius as you have that set to the minimum (ie light will not penetrate and scatter very far into the material, so the effect will be at its least noticeable). See https://support.chaos.com/hc/en-us/articles/4528339318289-What-are-the-two-available-SSS-modes-C4D
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2022-06-06, 14:08:43
Reply #2

Mac3DX

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Hi Tom,
Thanks for your reply, but it doesn't make sense at all; increasing the radius will make the chocolate look like wax. Going over 100% for the fraction may do the job.
We have here a clear example where SSS in Corona lacks functionalities in order to achieve the desired effect easily. Also, chocolates have no Volumetrics attributes (refraction) IMO, so we should be able to solve that in the SSS tab.
Vray has a much more advanced setup for this. I think we should review SSS in Corona, don't you think?

Thanks
Ricardo

2022-06-06, 14:36:45
Reply #3

TomG

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Can you share the result of increasing the radius, to show that it does look like wax (or doesn't - I should think small increase in radius will not make it look like wax and enhance the strength of the effect as you are looking for, but a quick test would put that question to rest :) )
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2022-06-06, 14:38:07
Reply #4

Beanzvision

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I'm no chocolatier ;) Are you working in scale at all?

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2022-06-06, 16:35:28
Reply #5

Mac3DX

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Hi Bengamin, thanks for your help but it seems dull and plastic. I came to this result with volumetrics but there is no need to use Volumetrics for this, it could be solved in SSS tab if we had a few extra simple controls. Take a look a t the simple material SSS properties in Vray and you're going to know what I'm talking about.
If you want to keep SSS simple as it is and transfer these more advanced SSS controls to the Volumetrics tab, I think the team should rethink some more logical/intuitive properties, because in terms of material feedback it is confusing. It's a matter of guessing, specially for the colors.


2022-06-06, 16:51:54
Reply #6

Mac3DX

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Can you share the result of increasing the radius, to show that it does look like wax (or doesn't - I should think small increase in radius will not make it look like wax and enhance the strength of the effect as you are looking for, but a quick test would put that question to rest :) )

Sure, take a look, we lack this control for achieving a more dense/hard material but still with small SSS over the edges. Increasing the radius also makes it flat, losing texture.

If we could go over 100% on fraction we will have control of the glowing intensity for the SSS. Also, a sort of back/front lighting balance control, would help to control how soft or hard the surface is.




2022-06-06, 17:24:00
Reply #7

maru

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Here are some experiments. I used Max, but the material settings should be the same and have similar names, so I hope it helps.
Please keep in mind that when dealing with SSS/volumetric stuff, the lighting plays a huge role. It would be best to try to replicate the lighting that you see in your photo references. For example, in one of the photos you posted in another thread I saw that there is a strong light source reflecting in the front sides of the objects (https://forum.corona-renderer.com/index.php?topic=36813.msg199448#msg199448).

1) SSS
Using one color to define surface color and SSS, but the surface color is much darker (using the diffuse level multiplier set to a low value). There is nothing "special" about this setup. I think maybe it looks a bit more like some kind of caramel than chocolate, but maybe it could look better with some more tweaking.

2) Volumetrics
Using no diffuse surface layer at all (refraction set to 1). By default, this produces bright, blurry glass. Then its volume is defined using absorption (black color - colored absorption is evil, you don't want to mess with it, believe me) and colored scattering. The positive directionality (+0.5) was giving a nice effect of "translucent" edges. The bright "sheen" effect is interesting and it does not really come from sheen, but from the rough refraction.

3) Legacy Mtl
I tried using the Legacy Mtl because it allows you to use translucency without the "thin shell" option, which often looks pretty much like SSS. The translucency effect is set to 100% to negate the base surface color, then the absorption is enabled (pure black again) and scattering is enabled. The interesting thing here are the bright highlights on the sharp parts of the geometry (like the cuts in the center). This is thanks to using the white translucency, and it is also something we see in the reference photos (although not so extreme).

If you find this helpful, feel free to experiment further with the material setups and lighting. I think the lighting is the key to success here (e.g. placing a light behind the chocolate objects can produce some interesting translucent see-through effects).


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2022-06-06, 18:57:27
Reply #8

Mac3DX

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Hello Maru,
Yes, light plays a big role in SSS, but I'm talking about those samples I provided in this thread. For a more obvious result, we usually use lighting from behind the object and this is being done here.

1- SSS
Again, it's visually clear that this feature is pretty poor and needs to be implemented, your chocolate material with it looks like watery chocolate or a candle in my opinion. That is, never use SSS for chocolates.

2- Volumetrics
I will explore this approach, but I have to be honest, visually the worst option of all.

3- Legacy Material
I found it interesting and I'm going to play with the values. The making of the edges shining is very interesting, although the color is not the desired one.
But at the same time, I don't think we should invest time in something that is becoming obsolete since the new approach is Physical Material.

I really appreciate your help and I will try some more. But the point here is, the tool needs to be better and more intuitive. Just evaluate how V-ray works, a product from the same company, correct? I know maybe this feature doesn't have a big impact on architectural rendering, but for food and products it's crucial.

Thanks,
Ricardo


2022-06-06, 19:08:23
Reply #9

Mac3DX

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2) Volumetrics
Using no diffuse surface layer at all (refraction set to 1). By default, this produces bright, blurry glass. Then its volume is defined using absorption (black color - colored absorption is evil, you don't want to mess with it, believe me) and colored scattering. The positive directionality (+0.5) was giving a nice effect of "translucent" edges. The bright "sheen" effect is interesting and it does not really come from sheen, but from the rough refraction.


I think I found something more coherent here. Leaving the absorption color black allows us to work the SSS along with the Directionality parameter but if we want to decrease the intensity of the SSS effect by lowering the Scattering Color level we will add black and not the base layer color. Why?
« Last Edit: 2022-06-06, 19:31:24 by Mac3DX »

2022-06-06, 19:59:56
Reply #10

BardhylM

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 -Just to chime in and give an argument on the opposite, not that necessary the tools do not need to advance. I just think the system corona uses it's quite simple for most of the cases.
Can't argue that it serves all the materials that you can think of, wouldn't think so. But I personally love the current system of SSS in corona, and Hated it in Vray. So many variables that maybe I didn't get to comprehend some why they were even there.

 -That said I made two small tests trying to come close to the reference you posted, made them in Max not in C4D sorry, but I think the concept stands. There are small variances even slight tints that make or ruin this material. You need to set the lighting and the color correction/tone mapping first so you can get good results, it matters a lot (even a Lut can change everything)
I tried two options, both in Physical Material:
One is with Subsurface Scatter the other with Volumetric Scatter. For these I didn't use any black colors just colors close to the reference (Used curvature map for lighter corners), also for the transparency I did not make it completely transparent.

Maybe not the best, but just to show you can get a good base for better refinements later.

2022-06-06, 20:08:38
Reply #11

Mac3DX

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3) Legacy Mtl
I tried using the Legacy Mtl because it allows you to use translucency without the "thin shell" option, which often looks pretty much like SSS. The translucency effect is set to 100% to negate the base surface color, then the absorption is enabled (pure black again) and scattering is enabled. The interesting thing here are the bright highlights on the sharp parts of the geometry (like the cuts in the center). This is thanks to using the white translucency, and it is also something we see in the reference photos (although not so extreme).


That's it! Boom! Mixing Translucency with Volumetrics SSS can offer full control over the desired SSS outcome. We should be able to do that with new Phisical Material also. Something to be discussed to the future realeases.

2022-06-06, 20:16:31
Reply #12

Mac3DX

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-Just to chime in and give an argument on the opposite, not that necessary the tools do not need to advance. I just think the system corona uses it's quite simple for most of the cases.
Can't argue that it serves all the materials that you can think of, wouldn't think so. But I personally love the current system of SSS in corona, and Hated it in Vray. So many variables that maybe I didn't get to comprehend some why they were even there.

 -That said I made two small tests trying to come close to the reference you posted, made them in Max not in C4D sorry, but I think the concept stands. There are small variances even slight tints that make or ruin this material. You need to set the lighting and the color correction/tone mapping first so you can get good results, it matters a lot (even a Lut can change everything)
I tried two options, both in Physical Material:
One is with Subsurface Scatter the other with Volumetric Scatter. For these I didn't use any black colors just colors close to the reference (Used curvature map for lighter corners), also for the transparency I did not make it completely transparent.

Maybe not the best, but just to show you can get a good base for better refinements later.

Hi, so kindy of you. Thank you.
Would you mind to share a screenshot of yo setup, I didn't have a chance toplay with curvature maps yet but it seems to be a good workaround to get those glowing edges.

2022-06-06, 22:09:05
Reply #13

BardhylM

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 -Glad if I pointed something to help.
The curvature map is nothing special, see attached image. It is used in diffuse and color similar in volumetric scattering(no map).
Also set a distance that corresponds with the scale.

2022-06-07, 10:22:04
Reply #14

maru

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Here are some new ideas.

1) Using the skin material
This is a bit creepy, but I thought it might work since you would like to see different layers of the material (e.g. the strong white effect on the edges, darker color in the inside).

2) Simulating the Legacy Mtl translucency with Physical Mtl
You can use the Layered Material for this. First, set up the material that will represent the medium (volumetric component) of the material - opacity 0, brownish color for scattering. Use this as the base layer of a Layered Mtl.
Then create a new material and set it up as the surface layer (top layer of the Layered Mtl). You can enable translucency here, and it will work pretty much like the Legacy Mtl from my previous example, but with the benefits of using the Physical Mtl such as better looking reflections.

3) Using a similar Layered Mtl setup again, but this time with rough refraction instead of translucency.

I also have a general note:

I understand that you are frustrated, because you are not able to get the effect you are after, but please note that comments like this are not welcome. If you are experiencing some issues, please explain what exactly is happening so that the community/team can help you. Such comments can lead to simply ignoring your posts, as they do not sound serious. Please bare in mind that Corona developers worked really hard on implementing all the features, and that their work is often based on years of research by themselves and other people:

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

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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.

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the tool needs to be better and more intuitive

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SSS (poor funcionality) and Volumetrics have confusing parameters

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the simple SSS in Corona are very bad IMO

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Even Modo crap can be better in Render times for SSS

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The effect is to weak and we should be able to go further than the 100% in order to achieve a more real visual representation.

As you correctly noted, Corona is mainly targeted towards archviz. V-Ray is more flexible and it is easier to achieve fakes in it, most probably including what you called "enhancing over 100%". Feel free to use the V-Ray trial, or contact our support at https://support.chaos.com/hc/en-us/requests/new
We will be happy to discuss the use cases and limitations of both Corona and V-Ray.











Marcin Miodek | chaos-corona.com
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