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From: Jeric@cup.portal.com
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To: lightwave-l@netcom.com
Subject: Re: Steamed
Lines: 54
Date: Thu, 16 Feb 95 00:23:36 PST
Message-ID: <9502160023.1.25381@cup.portal.com>
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>I am trying to create realistic steam on a cup of coffee. I am using a cone
>with fractal noise transparency and transparent edges. This works fine,
>except the top of my steam cone comes to an abrupt end.
>
>The closest I've been able to come is setting the diffusion of the cone with
>a horizontal gradient, but this really just turns the top steam darker, it
>doesn't make the steam fade to transparent (works o.k. with dark backgrounds).
>
>Morphing to another object with gradient transparency doesn't work either,
>as the bottom part of my steam just starts to look solid.
>
>All I want is a realistic looking cup-o-joe!
I had exactly this same question last year.
To achieve dual transparency, you need to combine FALLOFF with trans-
parency. Searching archives.....<not finding....>
...ok, I just made this surface. The important thing is, the VALUE in
the fractal noise requestor is what the value of the texture is when
the fractal=1. So, if you set VALUE to 50(%), then whereever the fractal
equals 1, the transparency there will be 50%.
But, if the absolute transparency is 100%, in the main surfaces panel,
then you can get it both ways, i.e. you are making it opaque, not xparent.
Below, a uuencoded Y-axis dual transparency surface: