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From: Louai Abu-Osba <me@louai.org>
Date: Thu, 6 Sep 2012 15:38:53 -0400
Message-ID: <CABan1zMcJhzSPeLyw2=Q6W9WWvFJKS_zbgrw6HqqRP5ZcRt1xg@mail.gmail.com>
Subject: Re: [AE] "conditional" blending layers
To: After Effects Mail List <AE-List@media-motion.tv>
Content-Type: text/plain; charset=ISO-8859-1

Actually, instead of using an effect to set the blending mode, you
could have duplicates of each layer, each set with the blending modes
you want, and then using the collision expression to turn their
opacity on and off so the one you want is blending. I think...

On Thu, Sep 6, 2012 at 3:35 PM, Louai Abu-Osba <me@louai.org> wrote:
> I think so. You'd need to use an effect that allows you set blending
> modes, and then use sampleImage() to detect when the layers overlap
> and then set the effect properly. Take a look at
> http://www.motionscript.com/design-guide/collision.html
>
> It would probably run pretty slow. If expressions run too slow AE will
> sometimes turn them off without telling you!
>
> -louai
>
> On Thu, Sep 6, 2012 at 2:28 PM, Teddy Gage <teddygage@gmail.com> wrote:
>> How would I go about creating a "conditional" blending layer? What I mean is
>> it possible to have say five circles called A,B,C,D,E randomly floating in
>> space and overlapping, such that unless A is over B, A has "normal" blending
>> mode, but when A overlaps B, it has an "add" blending mode? And then when A
>> overlaps C it has multiply blending mode instead, just as an example? This
>> is a puzzle...
>>
>> --
>> Animator & Editor
>> www.teddygage.com
>> Brooklyn
>>