Sponge material

[gagui]

Hello.

I just wanted to know what is the best way to create a realistic sponge material in vray.
I've searched the forum but all the related posts are very old.

I know there's the environment fog tool but it is prety limited for this task as it's impossible to assign it a material.
I read about Volume grid too but as far as I know it only works with vdb files and I want to assing this material to scene objects.

In arnold there's something like volume displacement. Is there any way to have similar shader effect in Vray?

[fixeighted]

You can try with VrayScatterVolume with a Bercon noise in various channels...may get you some of the way there.
And with Vray displacement mod also of course.

[gagui]

The problem I found with VrayScatterVolume is that it gets black where the texture is black instead of a volumetric surface:


Maybe I am doing something wrong.

I'm looking for something like this:

[fixeighted]

Yeah you'll need to experiment with the shader to try to achieve what you need. It's a tricky one
and there aren't many resources which cover the workflows.
If I have time I'll try and work up a simple scenario. Others here may know better or have other suggestions.
However, what I notice is that your reference is a bit less volumetric I'd say...more of it can likely be done with displacement of properly modeled geometry, don't you think?
So maybe start with a good, modeled representation and then fill in the gaps. The reference seems to show both solid 'metaball ' like structures and other, secondary, thinner forms.
So the only spongey stuff could be done separately from that. Just a thought

[Joelaff]

You can indeed apply a texture to an empty VRayVolumeGrid. You don’t need to load a VDB or AUR.

Set the dimensions of the grid in the settings, and apply a texture. It’s pretty cool when it suits your needs.

It is kinda slow to render, but manageable.

[M.Max]

I did write a post about volumetric a few months back on my Facebook that might help, so I will just copy it here :
"You can use empty VRay volume grid to fill an object with some clouds using a combination of Vray distance map (recently supported by V-Ray GPU ) and some noise maps.
For the distance map, you can enable "inside separate" with white color for the inside to actually fill the object or you can leave it off and keep the clouds near the object surface only (like the render here ).
the cool thing about this method is that you don't need to do any sim and it is fast to render."
Download max file (2017+)
https://www.dropbox.com/s/i3meobe7c8viz6h/fill%20object%20clouds_2017.rar?dl=0

[Joelaff]

Very Nice!

[fixeighted]

Yeah that is a cool idea, thanks for posting it

Another bizarre case of 'why isn't it in the docs?'

[M.Max]

Yeah that is a cool idea, thanks for posting it

Another bizarre case of 'why isn't it in the docs?'

You're welcome!
I can't take the full credit here, as the main idea is actually from the documentation Here .
The video shows the process of texturing the Volume Grid and I've just added the distance map to the mix.

[fixeighted]

Ah ok...I would not have thought to look there. It should really be in the main material section I reckon or a link to the courseware at least.
I did actually see the vid of the city setup but that was from just regular online searches.