View Full Version : alphas and spectral clouds

01 January 2007, 07:50 AM
hi all
I can't seem to pull an alpha matte on my scenes with cloud fomations. I want to generate some nice clouds in vue6 and comp them into a live action plate - but they seem to be ignored by the alpha chanel.

Am I doing something wrong? I tried putting an alpha plane behind the clouds, but that made no difference it only masked out the sky - not the cloud.

is this a 'feature' I wonder ?

01 January 2007, 07:03 PM
If you use volumetric layers, you can't separate them for the sky, they're part of it, so you need to use metacloud objects.

01 January 2007, 04:03 PM
I tried Using metaclouds.. I still don't get an alpha .. of just the cloud ..

01 January 2007, 04:59 PM
Exactly - no matter how much I play with it, i just can't get a mask of my metaclouds/spectralclouds

Doing multi-pass/g-buffer doesn't matter either. load up the layered PSD file and no mask data for the cloud, only planes like ground and water etc.

01 January 2007, 08:22 AM
Maybe MetaClouds against the 'Mask' atmosphere (I forget what it's called - the plain black one), and a 'screen' transfer mode or similar onto your footage might do the trick?

01 January 2007, 01:52 PM
meta coulds don't work with the mask atmospheres .. they only work with the spectral atmospheres.

Grrr.. . . that's lame .. how can they not have alpha setup in a 3D porgram .. !! ..

01 January 2007, 10:17 PM

How about creating a huge black plane behind the clouds and using that as your alpha


02 February 2007, 12:31 AM
or greenscreen inside vue :shrug: and later compositing it

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02 February 2007, 12:31 AM
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