Creating clouds

[fasterG]

Hi!

I need to create a cloud sequence for an upcoming project. The camera will move in all directions so the clouds have to be 'real', as in volumetric.
I'm a VRay-Maya user and not very familiar to Phoenix yet, but I've seen a couple of aerial cloud shots here in the forum that look great.

Is it possible to create different clouds and then import them into a new scene to populate a cloud landscape (similar to importing poly objects as proxies or references)?
I'm aware that render times can be massive, but maybe there are ways today to make it more reasonable?

Any cloud experts?
Thanx folks!

[sebbiej]

Hi,

This should be really useful for you: 200 clouds that you can download and open in your package of choice. I'm having difficulty getting them to render with distributed rendering though.

https://cubebrush.co/byvfx/products/...openvdb-clouds

Let us know how you get on.

[super gnu]

cooool! downloading now.. i had the idea to crank out a set of vdb clouds to sell, but somebody beat me to it! not looked through them yet.. hopefully there is lots of nice variety.

[fasterG]

Thats funny, I found that collection earlier today and I'm doing some tests with the free sample cloud atm
Without the farm, so can't yet tell if distributed rendering is working or not.

You import VDB clouds to a VRay volume grid, correct?
Right away there is an alternative to load a render preset depending on the clouds' origin (FumeFX, Houdini, Maya Fluids or no preset).
I found that 'No preset' seems to work Ok for this particular cloud. The Maya fluid preset is way too opaque.

A volume grid can't change the look and feel very much? (the opacity curve and light scatter multiplier seem to be only settings that affect the render).
So I guess its important that the VDB cloud has the right amount of complexity for your project?

[super gnu]

well you can use 3d procedurals to modulate the opacity/shading to add detail .. you can use vraydistance tex linked to geometry to sculpt or punch holes in it, but doing those things bump up the rendertime quite a lot.

[super gnu]

hm .. downloaded them.. cant complain for the price i paid, but they all have the same shape (one shape for round, one for flat) with just the details changing.. i guess there is still room for a set for sale with a bit more variety and some consideration of real cloud types.

[sebbiej]

Thats funny, I found that collection earlier today and I'm doing some tests with the free sample cloud atm
Without the farm, so can't yet tell if distributed rendering is working or not.

You import VDB clouds to a VRay volume grid, correct?
Right away there is an alternative to load a render preset depending on the clouds' origin (FumeFX, Houdini, Maya Fluids or no preset).
I found that 'No preset' seems to work Ok for this particular cloud. The Maya fluid pre-set is way too opaque.

A volume grid can't change the look and feel very much? (the opacity curve and light scatter multiplier seem to be only settings that affect the render).
So I guess it's important that the VDB cloud has the right amount of complexity for your project?

I used the Fume FX preset (as a random selection) and found the clouds to look pretty good out of the box, as such.
Changing the Simple Smoke Opacity, Smoke Color, and the scales seemed to have the most effect on the clouds for me. I couldn't find any way to increase the resolution though, they can look a bit 'blocky' if you have them too large.

We don't currently have a solution to creating clouds in-house, so this was a good find! I only found it the other day by chance.

If someone were to create a more varied library of clouds, please let me know! We do lots of in-air flybys of planes, so being able to create massive cloud environments easily, would be really beneficial.

As they take a long time to render as we can't use DR, I'm creating still renders of a few of the clouds then applying them to polygon cards, that are then scattered with MASH in Maya... I've found it's a fairly good way to get a big cloudscape if a little limiting.

[fasterG]

Super gnu: yea I noticed that too, looking at the previews. Just two different big shapes with small variation of details. But maybe cool to build your own bigger cloud constructions from these pieces? Provided they blend nicely together!

Sebbiej: Ok I'll try the Fume FX preset later. Exactly, the resolution would be so sweet to control to avoid blockiness. The volume of 200 clouds come in two resolutions, hope the hires ones are creamy and sweet

[Neilg]

Hi,

This should be really useful for you: 200 clouds that you can download and open in your package of choice. I'm having difficulty getting them to render with distributed rendering though.

https://cubebrush.co/byvfx/products/...openvdb-clouds

Let us know how you get on.

They look like pretty basic & quick houdini exports straight from it's generator. Which can be done with the free/trial version of houdini. Probably took him a day to generate them all and another day to package them up for sale.

They really need a little bit of wind to push them into new shapes once they've been generated as an amorphus ball of fluff like that - given some weight and movement.
New versions of phoenix can load these as their first sim frame, or maybe it's just nightlies - I requested this some time ago and it was added within a day!
It's probably better to get houdini yourself and generate your own clouds rather than buying those, then set up a couple of phoenix sims which pull the simulator through space to introduce some drag. The cloud generator is a single node and out of all the things it can make requires possibly the least amount of actual houdini knowledge.

[sebbiej]

They look like pretty basic & quick houdini exports straight from it's generator. Which can be done with the free/trial version of houdini. Probably took him a day to generate them all and another day to package them up for sale.

They really need a little bit of wind to push them into new shapes once they've been generated as an amorphus ball of fluff like that - given some weight and movement.
New versions of phoenix can load these as their first sim frame, or maybe it's just nightlies - I requested this some time ago and it was added within a day!
It's probably better to get houdini yourself and generate your own clouds rather than buying those, then set up a couple of phoenix sims which pull the simulator through space to introduce some drag. The cloud generator is a single node and out of all the things it can make requires possibly the least amount of actual houdini knowledge.

Fair enough, that's good to know!

I'd love to get Houdini myself, but trying to get the company I work for to buy it is a bit of a problem... For the moment the team is using Elementacular, which isn't exactly great. I might see if I can get a trial of Houdini to get to grips with it, anyway.

[Neilg]

I might see if I can get a trial of Houdini to get to grips with it, anyway.

Apprentice version is free to learn.
I am willing to bet those clouds for sale were exported using the apprentice version too. They dont strike me as the kind of clouds someone who paid for the software would be making, they're pretty much default cloud generator with the seed changed.

[fasterG]

I'd love to get Houdini myself, but trying to get the company I work for to buy it is a bit of a problem... For the moment the team is using Elementacular, which isn't exactly great. I might see if I can get a trial of Houdini to get to grips with it, anyway.

I also used Elementacular last year and I agree, it seems to lack something (even if I probably butchered the Vray grid settings!). Which is a shame, I really liked the simplicity and intuitivity of the Elementacular workflow.

I've only done some quicker tests so far with these new VDB clouds, and I ran into some issues similar to last year:

First, how should I think about the render settings when working with VDB clouds? They seem to get bypassed in some way; absolutely no difference in render time between min 1 max 24 (subdivs), thresh. 0,01, and min 1, max 2, thresh 1,0 ^^ (bucket mode).. No reaction from the Min shading rate slider either.
Same kind of minor noise (which actually is ok if unchecking 'Animated noise pattern').
Noise is greatly reduced when turning on GI (and render time naturally goes up).
Noise is getting REALLY serious when duplicating more clouds in the scene. As if they all share some kind of common 'pool of quality', that decreases exponentially with larger quantity.? Is duplicating vs instancing a big factor?
Which lighting setup is less hard on the render times; dome+directional light or sun&sky?
Is it possible to get a z-depth pass from the clouds, for controlling a fake fog in post?
Light rays.... is a cube with environment fog (constrained in front of the camera) the way to go?
IPR is not updating when changing light direction. Is it as it should be? (Maya 2018, VRay 3.60.04)

Yeah I need to get the head around the settings. Hints are greatly appreciated : )

[Svetlin.Nikolov]

Hey,

This question is answered roughly every two weeks here in the forums, but just in case - the options you need to look at are Volumetric -> Smoke Color -> Light Cache Speedup / Light Cache on/off + Environment -> Phoenix FD Atmosphere -> Probabilistic.

Hope this helps

[fasterG]

I continue the cloud scene in the new amazing VRay Next.

In 3.6 there was a VolumeGrid -> Render Elements tab where I could turn on ZDepth.
It seems to have moved inside the Volumetric tab in Next (Volumetric ZDepth set to Standard channel)? But now my ZDepth RE just renders black. Even for the scene that worked before.
Where did I go wrong?

Edit: Separate channel + ZDepth RE works. All good. I would delete this post if I could