Rendering Clouds again

[mash]

Hi, I'm back again with a cloud question.
So I need to render the sky and clouds as separate layers.
What I need to do is be able to comp the sky and clouds
Back together in Photoshop and then be able to erase or move certain clouds.
Why? Because the director is a nut case. 
I can render the sky without clouds OK.
But when I render the clouds without the atmosphere and comp them back over the sky
and erase the Clouds there is noticeable difference.
I think this is Because when the clouds are rendered it also adds a layer of fog to the atmosphere.
So is there anyway to render the sky and all the clouds passes as separate layers,
With a built in Alpha? Not just a separate alpha pass?
And still keep the effects of all layers intact?
Thanks, Michael

[Oshyan]

I don't think there is a way (or at least a reasonably simple way) to do this at this point. But I'll have Matt check-in if he knows of a way.

- Oshyan

[JimB]

This might help:

Try disablling the Atmosphere's Primary Rays. Then split your clouds into layers by cannily using Distance Shaders and render them separately, being sure to render an Alpha as well (I'm assuming you have the Deep version of terragen?). Then switch off the clouds and render the sky alone.

Did it on a job earlier this year, and was able to pretty much automate the process by keyframing the Distance Shader settings. To create a band of cloud, mix two Distance shaders using a Merge Shader node, or use Jo's method here:
http://forums.planetside.co.uk/index.php?topic=4390.msg46184#msg46184

Maybe this will help as well:
http://forums.planetside.co.uk/index.php?topic=3194.msg32700#msg32700

[mash]

Hi, JimB thanks for the information. I'll give that a try today.
I can't figure what worries me more. The fact that you have a Roman Soldier as an avatar or the fact that I almost can almost name what time period in Roman History it came from.
I gotta get out more

If separate clouds renders are not possible now suggest it to Matt as a distant future feature request.
By the way Yesterday I was showing some of clouds I had already rendered and the VFX sup and the Comp sup  asked "Where did you get that Photo of the clouds?"
I guess you can pass that along as a compliment.
Thanks, Mike

[JimB]

I can't figure what worries me more. The fact that you have a Roman Soldier as an avatar or the fact that I almost can almost name what time period in Roman History it came from.
I gotta get out more

Mid-1st-C AD, Rhineland - http://i75.photobucket.com/albums/i311/tarbicus/ross_virtus_09.jpg   

If separate clouds renders are not possible now suggest it to Matt as a distant future feature request.
By the way Yesterday I was showing some of clouds I had already rendered and the VFX sup and the Comp sup  asked "Where did you get that Photo of the clouds?"

Isn't that just the best feeling!    

[Oshyan]

We intend to significantly expand the ability to render out separate elements in the future for exactly these kinds of purposes.

- Oshyan