Cloud rendering, with alpha??

#1

Hi there,
I was just looking into vue to create some cloud backgrounds for an animation I am working on but I ran into a bit of trouble and i was wondering if anyone could clear this up for me.
Is it possible to render out clouds without the coloured atmosphere background, or with an alpha so you could comp them over things later?
Thanks
Pete

#2

No, it is not possible. It is possible (sort of) with metaclouds, but not spectral cloud layers.

#3

damn, that sucks.
Oh well thanks for the heads up

#4

I used the following workaround on a project recently. Worked really well with lots of wispy cloud layers - don’t think it would have been as successful with large, solid cloud formations. See if it works for you:

  1. Render out the sky as normal (clouds + atmosphere + effects etc…)

  2. Hide all cloud layers, and render again. This will give you the sky gradient, but without the clouds.

  3. Use a ‘subtract’ node in your compositing package of choice to subtract the clean sky from the complete render pass (i.e. in shake use the ‘isub’ node)

  4. You will then have the clouds as a separate pass, to be tweaked as required. To get the original sky, simply composite the extracted cloud back over the clean sky using an ‘add’ node.

Note that you could selectively show one cloud layer at a time, and extract each one separately.

Does that help? It might be simple enough that you’ve already thought of it, in which case I apologise, but I thought I’d chuck it up anyway.

AJ

#5

Hehe, crazy but it sounds like it might work.
Thanks I’ll give it a go for sure!

#6

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