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Change opacity based on layer's position

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Igor HarmendaniChange opacity based on layer's position
by on Sep 17, 2012 at 5:07:40 am

Hello, everyone. I have an issue here, let's see if I can explain it clearly:


Let's say I have a blue solid and a text layer. The blue solid is masked and still, and the text is kind of rolling up the screen.

What I wanted was: everytime the text passes by a certain point (the middle of the screen, for example), que blue solid changes its opacity from 0% to 100%, and when the text goes away, the solid goes back to 0% opacity.

Is there any way I could do that without using keyframing? Since I'll have multiple lines of text keyframing would take too much time to do.


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Vishesh AroraRe: Change opacity based on layer's position
by on Sep 17, 2012 at 11:57:42 am

Mr. Harmendani

If the Spaces between the text lines are same, You can try to loop out the opacity or blue solid.

Try this:

1. Key frame the "Opacity" of Solid for one Text layer. From 0 to 100 and then from 100 to 0. This means you have 4 key frames.
2. Now Press T to reveal opacity of solid and Alt Click the Watch. This will bring out the Expression controls.
3. Now, Go to "Expression Control Menu" button(next to pick-whip). Select Property>LoopOut(type=circle,numberkeframes=0).
Make sure all of your key frames are selected.

You can adjust the timing of Opacity Keyframes according to requirement.

Vishesh Arora
VFX and Motion Graphics Artist

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Igor HarmendaniRe: Change opacity based on layer's position
by on Sep 17, 2012 at 3:25:15 pm

Thanks for the tip, Vishesh.

But I think my space between text lines won't be the same at all times :(


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Vishesh AroraRe: Change opacity based on layer's position
by on Sep 17, 2012 at 5:24:01 pm

Mr. Harmendani

Try this out:
Just copy the set of keyframes(4 keyframes) and paste them at the required interval.

Not a difficult task as you just have to press "Cntrl/Cmnd + V" several times.

You can also increase or decrease the duration of Opacity animation if the speed of scrolling text is different.

Select the Corresponding set of key frames, Hold Alt and drag the Last key frame. This is way can manage timing also.

Vishesh Arora
VFX and Motion Graphics Artist

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Walter SoykaRe: Change opacity based on layer's position
by on Sep 17, 2012 at 7:04:03 pm

We could cobble together an expression driven by sampleImage() to figure out where there is active text, but if you can give us some more context and maybe a screenshot or two, someone might be able to propose another way of looking at the problem with a more straight-forward solution.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Igor HarmendaniRe: Change opacity based on layer's position
by on Sep 17, 2012 at 7:35:48 pm

Here, I found this video, exactly what I want to do

http://tu.tv/videos/rebuild-of-evangelion-2-22-dvd-sub-esp-p


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Walter SoykaRe: Change opacity based on layer's position
by on Sep 17, 2012 at 7:47:48 pm

Got it. This would be doable procedurally a couple ways:

You could build a wide, short adjustment layer and stack a load of effects like blurs, minimax or threshold, alpha levels, hue/saturation, distort, etc. to create the reactive flares.

You could also mask off a small area to use to drive the effect and use an compound effect like Optical Flares which can be driven by the luminance of another layer.

Basically, you want to think in terms of creating the result from only a narrow band of white-on-black input such that you get the effect when there is white, and you do not get the effect when there is black.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Igor HarmendaniRe: Change opacity based on layer's position
by on Sep 17, 2012 at 10:38:33 pm

Thanks for the tip, Walter, I almost managed to do it...

I tried the adjustment layer method, here's what I did:



I created a text layer and droped bellow the adjustment layer for the blurs, hues, etc. Then I duplicated this layer and droped it above the adjustment layer. But the distorted text is moving with the upper text layer, and I want it to stay still.

What should I do? I tried the Optical Flares method but it was to laggy for my computer.


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