VRay Clouds system

[Macker]

I know this has been mentioned numerous times before, and whilst I agree with Vlado's sentiments that it isn't strictly speaking the job of a render engine to impliment clouds, it would be amazing if it were a function within VRay.

I know there are a couple of plugins out there that do it, but I find them to be difficult to get to work properly and also fairly unstable and they always feel as if they've been dropped into max from their native programs (vue in mind) without any consideration for gui.

Could clouds not be an extension of the VRay Sky? Or even a seperate plugin in the same way PhoenixFD is? It would be something I'd happily pay for, given that anything that chaosgroup makes is generally absolutely solid and not prone to crashes. VRay is currently capable of rendering clouds, easily; I've done so myself before - but it is the shape, etc that makes them believable or not and the standard max procedurals don't provide enough control over cloud cover & shape.

Just a thought, wonder if anyone else feels the same?

[vlado]

So besides Vue, what about DreamScape?

Best regards,
Vlado

[joconnell]

Exactly, there's the actual volume rendering itself which vray has, but then there's the second part which is intuitive and controllable cloud modelling which is a bit more specific - are we talking about overall skies / atmosphere or individual clouds that can be sculpted?

[Macker]

Do you not have to use their proprietary renderer "rapidray"? And what about their shaders, etc?

[vlado]

Do you not have to use their proprietary renderer "rapidray"? And what about their shaders, etc?

I'm just wondering about the clouds...

Best regards,
Vlado

[Macker]

I guess all it would take (no idea how difficult they are to program) would be some procedurals that mimic different cloud types. Also, last time I tried to make my own clouds I had to use a gizmo that was several kilometers in size to stop the clouds from coming down to the ground, and to imitate the curvature of the earth so that the clouds would come down to the horizon several kilometers away!

Surely there's a better way of doing this?

Here were my results btw; http://www.youtube.com/watch?v=B4LBQM4iI8g

[alexyork]

This would actually be great.... some kind of tweakable atmospherics settings within the Daylight system, perhaps, or a dedicated Vray Atmospherics System. So you could choose between overcast, stormy (think dark blacks/greys and yellow sunlight coming through gaps), sunny etc. And a moon-lighting one too would be fantastic. And imagine if you could animate between them! So you could go from a dark and stormy atmosphere to a bright sunny one as the clouds part...

Perhaps custom cloud configurations using simple monochrome maps, or presets...

I think this would be extremely powerful.

[Macker]

Absolutely.

Whilst HDRi's are fantastic they are limited by two things;

1) Resolution - unless you want to get one of those spherocam hdr's to take pics of your scene the HDRi will usually need replacing in the backgrounds of high resolution shots.

2) Animation - they are still images. Enough said. This for me would be the primary reason behind having an atmospherics system. I have before replaced the sky with an animated one in after effects, and it's always looked pretty good - but it is a lot of extra work, and it again has its limitations.

[Neilg]

We've been using the vue plugin for a shot passing through the clouds at the moment and the results & level of control are amazing. I'd like the vray version to be like that because we only have 3 render licenses for it.

[anchovy]

Ive seen any number of techniques for the cloud body modeling but to get the correct look shading wise you need multiple anisotropic scattering of something that fakes it vs. just ray marching and single scattering. Here are some examples.

http://hal.inria.fr/docs/00/33/30/07/PDF/clouds.pdf
http://cs.bilkent.edu.tr/~cansin/pro...ouds-paper.pdf
http://www.youtube.com/watch?v=XLXU1o4F6pE

This is a rather spiffy way to model the form
http://nis-ei.eng.hokudai.ac.jp/~dob...ng_process.mpg

http://vimeo.com/16888626 This points to what I had mentioned about being able to perturb volumes with a map vs just confining the volume to a mesh as is currently the case with VRay volume fog



Fun stuff

-Michael

[simmsimaging]

This is a rather spiffy way to model the form
http://nis-ei.eng.hokudai.ac.jp/~dob...ng_process.mpg
.....

-Michael

That is cool.

[Macker]

Some excellent examples there. I think the main issue for me currently is getting the clouds shape to look realistic and be controlled by a prodcedural map rather than a mesh/gizmo to contain it. The Vrayenvironment fog produces good enough results so far, though those examples of multiple & anisotropic scattering are interesting, though presumably would be cpu/gpu intensive if implimented in a photorealistic render engine?

[Swahn_Kung]

I've also sought ways to make (in a workflow sense) solid individual clouds with Vray in 3dsmax.
Complex meshes to create very large puffy clouds tend to result in backfacing, which leaves annoying gaps in the volumetric effect when using it with VrayEnvironmentalFog.

So far I believe the voxel based capabilities you find in PhoenixFD is best suited to create individual clouds. To be honest I have not tested myself yet, but I have been recommended several times checking it out because it got a displacement system built directly into the volumetric effect itself, which means you can create puffy nimbus looking clouds without risking backfacing to occur leaving gaps in the volumetric effect (and you don't have to deal with heavy meshes in the viewport.)

[joconnell]

Complex meshes to create very large puffy clouds tend to result in backfacing, which leaves annoying gaps in the volumetric effect when using it with VrayEnvironmentalFog.

What do you mean by this? As in the mesh ends up overlapping itself which leaves internal gaps in the volume afterwards?

[Morbid Angel]

I think it will take as much time to write a cloud system as it did to write vray