Fill volume using VrayEnvironmentFog to create cloud sculpture

[kosso_olli]

Hello,
recently I was asked by one of our customers if it is possible to generate a sculpture made of clouds using CGI. Take a look at the attachment to understand what I mean. I tested it with VrayEnvironmentFog inside a closed volume (the geometry of the sculpture) and got quite good results using some complex noise textures in the fog density. However, as you can see in the references, the edge of the clouds are very jagged and irregular. That is hard to achieve using EnvFog. When I fill the volume, I get a very hard edge. I can use the fadeout option, but that is just a kind of falloff. What I am looking for is a way to generate more complex transitions and edges. What do you think?

Regards

Oliver

[joconnell]

A single mesh probably won't do it, you'd be better off for starters bumping up your volume objects mesh, and then using the normal displace modifier to make it's edge more irregular, then also putting noise into the opacity slot of the environment fog slot. What'd be better again is filling your object's volume with lots of max atmospheric sphere gizmos so you've little "puffs" and have noise in these too.

[kosso_olli]

Hat tip to Joconell,
tested his idea with distributing max atmospheric sphere gizmose along my model, works quite good!
Does anyone have an idea how I can make the inside of the clouds more of a blueish color? If I set the color to white, I cant get that effect. Putting falloff maps into the color slot of the EnvFog doesn't seem to change anything.

[joconnell]

The blue bits are just the absence of the direct light. Use a blue coloured domelight, and a warm coloured directional light for your sun. The blue sky light fills in the areas of the sunlight's shadow giving you that look.

[kosso_olli]

Okay, thanks. I thought it had something to do with the absorption and scattering of light inside the clouds because of the water vapor.

[Swahn_Kung]

What I miss with VrayEnvironmentalFog is the ability to displace the volumetric effect directly instead of having to rely on a high resolution mesh. I saw a white paper explaining the benefits of volumetric displacement for creating denser more puffy effects (without the broken noise edges). If I'm correct I think Cebas Pyrocluster have this feature. One of the benefits of having your displacement on the volumetric level rather than the mesh object level is that you, at least for Vray, doesn't get holes in the volumetric effect where the reference mesh is passing through itself to reveal backfacing.

I'd love to see true volumetric displacement for VrayEnvironmentalFog.

Edit: found the paper: http://magnuswrenninge.com/content/p...entals2011.pdf

[kosso_olli]

Swahn,
that is exactly what I would have needed in that current project! Anyway, ended up displacing the mesh with the method described by joconnel. I then rendered a sequence with different cloud sizes and setups, which gave the retouchers enough material to work with.

[instinct]

What I miss with VrayEnvironmentalFog is the ability to displace the volumetric effect directly instead of having to rely on a high resolution mesh. I saw a white paper explaining the benefits of volumetric displacement for creating denser more puffy effects (without the broken noise edges). If I'm correct I think Cebas Pyrocluster have this feature. One of the benefits of having your displacement on the volumetric level rather than the mesh object level is that you, at least for Vray, doesn't get holes in the volumetric effect where the reference mesh is passing through itself to reveal backfacing.

I'd love to see true volumetric displacement for VrayEnvironmentalFog.

Edit: found the paper: http://magnuswrenninge.com/content/p...entals2011.pdf

Without reading the paper you can do what you described with phoenix.

Regards,
Thorsten

[kosso_olli]

Is Phoenix up to the task of simulating smoke for very large print resolutions of lets say 10k? If so, I could consider trying it out.

[Swahn_Kung]

Without reading the paper you can do what you described with phoenix.

Regards,
Thorsten

Yeah I think that was the reply I got last time I posted about it here frankly. It's just that I find VrayEnvironmentalFog so much faster and easier to work with for things that are going to be animated as a fluid. But then again, VrayEnvironemtalFog is not voxel based so perhaps there is a fundamental limitation to it.