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Expressions Between Comps?
I’m new to expressions so forgive me if this is horribly basic. I’ve been getting by with simple expressions (wiggle, etc.) and I’m starting to think about how to use expressions to make my life a little easier. The only issue is that my brain doesn’t quite work that way so I’m coming up a little dry on this one.
Here is my situation. I have created a particle “fire” that grows and stretches out from left to right. I have a texture behind the “fire” that I’ve added the cc glass effect to in order to get something resembling a bump map. I would like to try and have the “fire” cast a reflection on to the texture.
Both the texture and the “fire” are nested comps. Can I somehow create an expression which would take the brightness values of the “fire” comp, and effect the position of the light property in the cc glass effect?
Does that make sense? I guess that it wouldn’t be a real reflection, per se, and I can wiggle the light property of the cc glass effect to achieve a nice effect but it doesn’t quite match the “fire”.
Any information would be great! Thanks again!
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6 Replies
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Sure, but you need to better define how you want it to work. What happens when the fire is at its brightest (and dimmest)? That is, what’s the relationship between the fire brightness and the light position?
Do you want to sample a particular area of the fire, or the whole image?
Dan
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Thanks for the response Dan! Motionscript.com has been a great resource and influence.
Not to be too greedy but I’m kind of interested in seeing how both would work and look. I was looking at an earlier post about the “sample image” expression but, as I mentioned, some of this stuff goes way over my head.
I’d be thrilled just to sample a portion of the image and have the “reflection” respond in kind. But I feel that seeing how both options look, and how they work, would be a fantastic learning experience.
Thanks again for the quick reply!
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sorry, I’m still not getting exactly what it is you want the glass effect to do in response to the luminance of the fire.
Dan
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I’m sorry for the confusion.
I’d like to link the light position property of the glass effect so that it corresponds to the brighter area of the fire. So when a bright area of the fire passes the texture, the position of the light property will move with it.
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Sorry, anything I came up with would just be a wild guess. It really depends on how you have things set up.
Dan
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