Hi.  It's been awhile since I have used Carrara and am very slowly working on a huge forest fire scene.  I have started out by using a volumetric cloud and three lights (Red, Gold and Orange) to make the flames.  I plan on doing post work in photoshop to blend things to look the way I want, but have hit a small snag.  I want to make  masks of the cloud at different transparency and settings, but don't remember how to do it.  I think it has something to do with the alpha channels, but am not sure.   Also what is the difference between: Render Alpha channel and Use Premultiplied Alpha?

Anyways here is a quick look at my progress so far.

Sincerely,

David

Good question.

I found out recently what the difference was between alpha channel and premultiplied alpha. If I remember correctly (I think Mark Bremmer enlightened this somewhere), the alpha channel is a mask for the objects based on the geometry. The premultiplied alpha also takes the transparancy in the mix. So if you have shader based transparancy (with alpha masks or 'transparancy' in the shader tree), you should render with the last option.

I am not sure about what clouds would need though.

Hope this helps!

Hoof

 Hi.  I have been playing around with the image in photoshop and here is a shot of my progress.  I still have a lot of work to do and any criticisms are encouraged.

Sincerely,

David

p.s.  Mark thanks for the soundtrack pro help.

 I thing you could do some more liquify or smear work, thus making the flow of the fire go upwards everywhere. But this is definitely a good start, especially when it is incorporated in a scene.

By the way, do you know Primivol, maybe that will solve your quest too: it is here