VrayFastSSS, does light actually go trough ?

[strongsacer]

Here is my issue :

I am currently trying to render drops of water (with a simple VrayMtl Shader).
They are laying on to a surface using Vray FastSSS.
It seems like the light doesn't go trough the SSS shader because my drops render black. (see small image below)

I did a simple test with a VrayMtl on my surface, it seems like it is rendering fine or at least the water drops looks like expected.



Does anyone had this problem before ?

Romain

[vlado]

Can you post a larger image? It's a bit difficult to see what is going on.

Best regards,
Vlado

[strongsacer]

Hi Vlado,

Thanks for replying.

Here some better images. I tried to do it in a much simpler scene.

http://www.romainfaure.net/downloads/vrayfastsss2.jpg

I figure out one part of my problem, but it still does not do what I'm expecting yet.

Here a reference image of what i'm trying to replicate :

http://www.romainfaure.net/downloads/reference.jpg

Thank you,

Romain

[Svetlozar Draganov]

What is the status of Affect Shadows check-box of the VrayMtl applied to the drops of water?
Would it be possible to attach that scene for investigation?

[strongsacer]

Here the files :

http://www.romainfaure.net/downloads...oughSSS_01.max

[strongsacer]

Here thew file :

http://www.romainfaure.net/downloads...oughSSS_01.max

[strongsacer]

Vlado,

I took some references photos myself.
Here the better pictures of the effect that I am trying to replicate :
http://www.romainfaure.net/downloads/leafimage_ref.jpg

[Svetlozar Draganov]

That is a much better reference image, thanks for taking it and sharing it with us.
The light that travels through the leaf is actually caustic effect generated from the drop of water behind the leaf.
In order to replicate that effect you need to activate Caustics under the GI rollout and make sure that the Affect Shadows option of the Water Material is disabled.
(For proper caustic calculations Affect Shadow should be always off)


scene: http://ftp.chaosgroup.com/support/sc...S_caustics.max

[strongsacer]

Thanks for your answers,

Another question about the way the refraction works. I'm not sure if it is a problem but it doesn't seem right to me :

I have this scene here, with a drop of water on the surface. Caustics are on. Here the 3dsmax file ( http://www.romainfaure.net/downloads/drop.max )

I would except to be able to see through the drop of water, wich is not the case. The drop is right above the ground. Image A (http://www.romainfaure.net/downloads/dropofwater.jpg )

I only see through the drop of water, when it is interpenetrating the ground, but then I lose the caustic effect. Image B ( http://www.romainfaure.net/downloads/dropofwaterB.jpg )


I would like to be able to see through with the caustic effect.

Thank you,
Romain

[Zdravko.Keremidchiev]

The effect is very dependent to the drop shape, the lighting and the angle of the camera. In your scene with your particular setup the reflection rays tends to hit the environment more, therefore you can not see the plane. Generally some imperfections can brake this effect, as well as different camera view and maybe an HDRI base lighting.