[noseman]

I am trying to make a plastic cap.
My Cinema 4D attempt is this:

My client liked it, but I want MORE! I want the maxwell look!

So here are my tests:
dielectric cap, nice roughness BAD colour..
Too transparent no diffusion at all (dielectrics have no diffusion properties)

*****
Too dark

*****
plastic with SSS (full = 1)
No translucency, I don't know why. Am I doing anything wrong?



The cap thickness is 0.5 mm and the scale is 0.001 (I am using mm)
Maybe it's the fact that the light has to go through 2 SSS surfaces (back and front)

Any ideas? Thanx!

P.S. The rest of the render is PERFECT (for my humble eyes), I can't get the bloody cap right

[DELETED]

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[noseman]

nice idea for a workaround, but I am seeking THE POWER OF SSS (echo - echo)




P.S. I'll try your solution later tonight, thanx!

[bathsheba]

nice idea for a workaround, but I am seeking THE POWER OF SSS (echo - echo)

Me too -- I feel like I'm missing something about dielectrics because I can only make them transparent, not translucent.

-Sheba

[Tyrone Marshall]

Hello Noseman,

Nice virtual samples!

You must have some absorption for SSS scattering to work with the Cinema 4D plugin.

Set your SSS absorption value higher than 0.

Remember, we have simple SSS for cinema4d. See Issue N03 below.

ref: http://www.maxwellrender.com/forum/viewtopic.php?t=4723

[noseman]

actually, I was aware of that Tyrone, so I set absorbtion to 0.05.
That is what you see.

I am running a test with absorbtion set to 0.5 and I'll post it later.

Edit: at sample level 8 I'm getting no SSS at all.
what I was wondering is that I have 2 fill lights, left and right of my camera and one top-back light (the one you see in the 2nd photo).
could it be that the diffusion from the two front lights burn the image to a point that I can't see any SSS?

[noseman]

Ok I've got it.
Listen up SSS lovers!

There is a major problem from using SSS for translucency... it's not translucency

Nobody said it was anyway. The biggest problem is that the SSS value is linked to the colour of the material (diffuse of plastic) so that when you have backlit SSS objects, it looks nice, but when you have environment light it tends to surpass the SSS that comes from the back light and that causes the object to seem opaque.

In my case (canister cap) the light that penetrates the plastic and lights the interior (in order for it to bee seen through the plastic) is much less than the light from the environment that lights the front of the cap.
This makes the cap seem 100% opaque.

A solution would be either a dielectric with an added diffuse parameter, or another material (e.g. plastic) with an opacity value.

Is that possible NL guys?

Thanx!

P.S. tyrone I dissagree with your post on issue N03, try the following test:

Make a very thin film with a cube primitive (500,500,0.01)
Make a sillouette (a freehand spline) of a hand for example and extrude it in the Z axis.
Set it about 150cm to the back of the film.
Set the film to a plastic with SSS.
Light the figure with a light pointing towards it so that it doesn't light the film.

You will see (after some time) the silouette showing on the film (blurry but there).
The emitter doesn't pass through the SSS object but the reflected light does.

It's purelly a "not translucency" issue.
We need more light to pass through the object and less scattering.

[Aldaryn]

I think to solve this, we will have to wait for a more complex shader modell. A dielectric (something capeable to transmit light without scattering it) with a diffuse component (diffuse reflect some light) with corersponding SSS properties (transmit and scatter some of the light) would do.

With very few parameters this model could be implemented.

[Tyrone Marshall]

Ok I've got it.
Listen up SSS lovers!

There is a major problem from using SSS for translucency... it's not translucency

Nobody said it was anyway. The biggest problem is that the SSS value is linked to the colour of the material (diffuse of plastic) so that when you have backlit SSS objects, it looks nice, but when you have environment light it tends to surpass the SSS that comes from the back light and that causes the object to seem opaque.

In my case (canister cap) the light that penetrates the plastic and lights the interior (in order for it to bee seen through the plastic) is much less than the light from the environment that lights the front of the cap.
This makes the cap seem 100% opaque.

A solution would be either a dielectric with an added diffuse parameter, or another material (e.g. plastic) with an opacity value.

Is that possible NL guys?

Thanx!

P.S. tyrone I dissagree with your post on issue N03, try the following test:

Make a very thin film with a cube primitive (500,500,0.01)
Make a sillouette (a freehand spline) of a hand for example and extrude it in the Z axis.
Set it about 150cm to the back of the film.
Set the film to a plastic with SSS.
Light the figure with a light pointing towards it so that it doesn't light the film.

You will see (after some time) the silouette showing on the film (blurry but there).
The emitter doesn't pass through the SSS object but the reflected light does.

It's purelly a "not translucency" issue.
We need more light to pass through the object and less scattering.

Noseman, please post more information on this finding- I would be more than happy to update my findings on SSS if you have better information.

So is there a work around with adjusting the material color (plastic/diffuse) maxwell render tag to get the SSS to work for light sources where the object is not backlit.

Thanks for looking into this issue.

[noseman]

Unforunatelly, not beeing able to vary the SSS amount (as I am a C4D user), I don't think my tests could at the moment give any worthy results.
I will wait for a more advanced C4D plugin and better SSS.

I will run all tests then.