I would love to see tutorial given by SESI for new stuff such as Cloud FX

SISI? Are you trying to taunt us into making the tutorial?

lol

rmagee
SISI? Are you trying to taunt us into making the tutorial?

YES . you guys done this before so it wouldn't hurts if you just did this for Cloud FX

http://www.sidefx.com/index.php?option=com_content&task=blogcategory&id=202&Itemid=361 [sidefx.com]

We have a lesson in the works - no definite date for release. I will keep you posted.

Robert

rmagee
SISI? Are you trying to taunt us into making the tutorial?

Lol, but a +1 nonetheless.

hey rob, any eta on the cloudfx tutorial? If not, any chance I can ask you some personal questions? trying to use this in production at the moment and could use some tips

Still working on the lesson. Ask any questions you want. It can be helpful when forming the lessons.

Ah cool, well, here we go:
My main issues at the moment is getting rid of the graininess in the render, it does seem that upping the volume quality (in mantra rop) works. Ideally I'd like to get the detail that lowering the div size (in cloud sop) gives me but without the massive render times.
Also I get a lot of popping in my shadows when I animate the clouds. not entirely sure what is causing that yet. I am animating the offset in the cloud noise to get some motion in them.
I am using the point cloud option so I have better control over randomizing the scale of the clouds as I can do that on a per point basis. Do you have any tips on randomizing the noise (or noise offset) on that same per point basis?
Thanks!

And a bug I just found:
if i use the size option in uniform sampling to give it the voxelsize there is something wrong. the more points i use the lower the resolution gets. where the point of using a set div size is that it will always have the same voxelresolution no matter on the amount of points.. right?

Hey sjowol,
Would be nice if you can post your file so I can see what's wrong.
For now, here is a file with a basic Cloud Rig and I've setup Mantra node with it.
I rendered with PBR. I haven't set the values to the maximum and it's already giving me a decent result and with no grain.

You can lower the Noise Level and have more pixel samples but not sure about your scene setup.

lari

looks awesome!
unfortunately not too much time to clean this up and post something but instead of just the one cloud i have about 1000 point scattered, copystamp spheres on top of that and then fill those with clouds… just quickly did that with (approx) your settings and get it super grainy. your max axis res of 100 is pretty high, for my scene that is simply not a feasible number, i am using div size of 0.04 any lower then that I crash (win7, 8core i7 3.33Ghz with 24 gig ram)

ok so it would still not help me to build the scene myself…
Can you send me just the geometry (copied sphere) and the camera of your scene? basically everything you built for the clouds but without the cloud rig.

I would be able to tell you what's going wrong and maybe be able to give you a different solution. This could help others in a possible same situation.

I did copy 1000 spheres and used the cloud rig and its working on my machine at 0.02…

thx
lari

well here is an extremely simplified version, sorry i don't have more time to get a better example at the moment

So is that the output that you get? because that doesn't seem that bad!
I don't see the grain you talk about. For sure we can see on the closest clouds the steps but for the mantra setting that you had it looks ok.

where you rendering with the preview mode in the render view?

lari

no i managed to get rid of the grain by setting the volume quality to 1 on the rop (default is .25) it is mainly the detail i am looking for and a good way to get some motion in the clouds. seems like ofsetting the noise does a decent job but then ideally i want to change the speed on a “per cloud” basis

So basically you can't have one scattering of clouds and expect to have the same quality for the ones close to the camera. Split them in maybe 3 different setups.
> a couple of High resolution clouds in front to the camera
> Mid resolution clouds further away like the file I sent you now
> Low resolution for the ones in the back.
This way you can optimize your scene and the ones in the far end won't have the same resolution as the ones up-close.

Check this file that I attached… this is one good way to scatter clouds without using a copy sop.

As for the movement of the clouds, you can get great results by animating slow change in the Noise offsets and the advection time variable. As for the per cloud speed control, I will have to take some time to see what could be done and i'll get back at you as soon as possible.

lari

cool, thanks!
unfortunately i do need the copysop in there as i need to run a disappearing effect on it later on. that also means i can not use the fill source and secondary shapes as these scatter points in the volume so when i shrink down the volume this will not be consistent

oh by the way larikaram, I was looking at your 1st file but if i render that, i get nothing like your attached image. still a nice cloud but missing the translucency and all

Yes, that's because you can play with a couple of variables to achieve that.

First one thing I notice is that you are working in non-Linear color space. This mean that your image will come darker than mine. It is always recommended (it's a good practice especially if your working in a production) that you work in Linear color space. There are tones of information on the web about the technical part of it which I'll spare you for now.
To switch to linear in Houdini, go edit > color setting > color correction, set your value to 2.2 and check all the other options that you want to affect (ideally all of them).

Now that said, you can play with your density and the ramp of the cloud. It will help the translucency effect.

Also if you check your cloudlight node in the cloud rig, in the light tab. You can put a brighter color to the light, for example a light grey. (which I think in your example I did a darker blueish). You can play around with the propagation tab but in my case I left it to default.

Last thing you may want to check is your shader. You have the Single Scattering Phase variable. This tells mantra how light bounces inside your cloud, which helps you get this translucency. By default, its at 0.2. Try a value of 0.5 or 0.6. That should give you a close enough results.

There is no specific recipe for clouds, it will depend on what type of cloud you want to achieve.

hope it helps

lari