How can I recreate the 3dsMax snow tutorial in Houdini? (SSS + Stochastic Flakes)

[4n7]

I'd like to create the snow shader shown in the 3dsMax version
https://docs.chaosgroup.com/display/...asticFlakesMtl

I see there is a snow shader in the Houdini docs
https://docs.chaosgroup.com/display/VRAYHOUDINI/V-Ray+Snow

but this is more for assigning the material to the top of objects, I'm after the SSS / Stochastic look from the 3dsMax tutorial, not sure how to blend these materials in Vray for Houdini

From what I understand I create a VrayMaterialBuilder, then within there I can add a 'V-Ray SSS' and 'V-Ray Stochastic Flakes' to a 'V-Ray Blend (Material)'

I can increase the BDRF Count to accept 2 inputs but when I connect them it doesn't look correct, how do I set the SSS as the base material and the flakes as a coat?
If I use the carpaint node it doesn't accept BRDF as the incoming connection

Thanks

EDIT: May have found the right option which is switching the blend to 'Additive'

[Muhammed_Hamed]

Usually you don't use additive mode in the blend material, it is not Physically accurate and will cause issues
Your issue is related to something else, the blend material in VFH works in a different way compared to all other Vray plugins
BRDF weight 2 is your blend amount 1 basically
What you need to do, is make BRDF weight 2 >> 0.5 (That is your flakes layer layer)
And BRDF weight 1 should be 1 which is your SSS layer( weight 1 is like an alpha for you base material, you don't have this control in other Vray plugins)

If you still cannot get the same effect, I can convert that file to Houdini and send it to you.. let me know

[chakarov]

Hello 4n7 Muhammed_Hamed is right, changing the weight_2 value to 0.5 will replicate the V-Ray in 3dsmax behavior of the blend material.

[Muhammed_Hamed]

I actually prefer how the blend material works in VFH, probs to the devs for this
It makes much more sense and I would wish other plugins would work in the same way. And of course you have control over the weight of your base layer which you cannot do in other plugins


Best,
Muhammed

[4n7]

Thanks Muhammed, I'll give this a try when I get the chance


Still not totally figured out the method of material creation, below is how I had set it up, I've imported the scene to Houdini from the vrscene export in 3dsMax, then imported the materials, looks quite similar.

Neither look quite right though, the imported material has the weight set via other nodes, and there is a MtlSingleBDRF node in between the layered and the output

[chakarov]

Basically material is the same, just weights are represented by colors and some default material options in 3dsmax are represented in MtlSingleBRDF.

Those "other nodes" used for weights are just colors, because in 3dsmax blending is controlled by colors, in VFH you can use colors or values. The MtlSingleBRDF is a part of the standard V-Ray material in 3dsmax which is separate node in VFH.

[woytha]

Basically material is the same, just weights are represented by colors and some default material options in 3dsmax are represented in MtlSingleBRDF.
Those "other nodes" used for weights are just colors, because in 3dsmax blending is controlled by colors, in VFH you can use colors or values. The MtlSingleBRDF is a part of the standard V-Ray material in 3dsmax which is separate node in VFH.

I am going through this tutorial as well now. Described approach looks OK on stills but in real life when you are moving, the flakes as well - but only when you (camera) are moving. Would you have an idea what is the best way to setup the stochastic flakes based shader for animation?
Thanks!