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Using a ramp to affect scale and opacity values?
I am working on a motion graphic and I got in over my head. I have 70-80 different texts and I am supposed to make them drop from the sky. My idea was to keyframe scale and opacity to make them look they are falling into view but I really don’t want to key frame all of them. And then offset those key frames.
Is there a way I am animate a ramp over my text and have the values of the text change from one value (white) to another value (black)? Sort of like a luma matte that also affects scale?
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5 Replies
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You could use the new image sampling expression function in CS3 to sample a ramp and scale your layer according to where its anchor point falls on the ramp… Something like this:
min = [10, 10];
max = [300, 300];
l = thisComp.layer("Ramp");
p = l.fromComp(toComp(anchorPoint));v = rgbToHsl(l.sampleImage(p))[2];
linear(v, 0, 1, min, max);
Apply that to your scale property, change the ‘l’ variable to the layer you want to sample, and pick new values for minimum and maximum scale.
Darby Edelen
Lead Designer
Left Coast Digital
Santa Cruz, CA -
I should add that this only samples at one point and scales the entire layer… So it’s not the same as a luma matte which changes the opacity on a per-pixel basis. If you want to fake scaling of a layer on a per-pixel basis you’ll need some fancy displacement mapping techniques.
Darby Edelen
Lead Designer
Left Coast Digital
Santa Cruz, CA -
I’m afraid that was going to be the answer. Thanks for your help but it doesn’t look like that is going to work.
Time to put on a Foo Fighters concert DVD and my sweat pants. Its going to be a long night.
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So now I’m confused… The expression didn’t do what you wanted it to? Maybe I didn’t understand what you’re attempting to do. Do you actually want the layers to bend and distort or only to scale? Where are they supposed to be falling from/to?
Darby Edelen
Lead Designer
Left Coast Digital
Santa Cruz, CA -
I might read your post wrong. I ended up doing it the hard way but I didn’t take as long as I thought it would. Thanks for your help though. I will probably try your advice at the end just to see how it works.
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