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Defining Min and Max
Alright, so, as I said before, I’m trying to get into writing expressions for myself when I need them, so I’ll probably be on here asking things as questions crop up.
I understand how to basically define an expression (position = thisComp.layer(“Null 6”).transform.opacity) that makes sense to me. However, say I wanted to say the position of a given thing is equal to the opacity of a given layer but between two numbers. I’m trying to think of the most concise way to say this. But if I wanted the position between 2500 and 3500 as the opacity went from 0 to 100. How do I get that going?
Thanks as always.
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2 Replies
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Interpolation. Click that little triangle next to the pickwhip, then select Interpolation, and you’ll see the forms (or see Help Files).
Anyway, if you trying to have the Z position (depth) to range from 2500 to 3500 as the opacity varies from 0 to 100 (I’m guessing that’s what you want) then this would be an expression that works (on position):
x = position[0];
y = position[1];
z = linear(opacity, 0, 100, 2500, 3500);
[x, y, z]So that third line is saying as the opacity varies from 0 to 100, then interpolate the z to be from 2500 to 3500. Linear is straigh proportional, and there are Ease form if that’s what you want.
Is that what you want?
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OK, after re-reading your question I see you asked for min and max values for input into your expression, so this is probably a better way to write it so you can see what min and max are for the various things you could change.
minZ = 2500;
maxZ = 3500;minOp = 0;
maxOp = 100;x = position[0];
y = position[1];
z = linear(opacity, minOp, maxOp, minZ, maxZ);
[x, y, z]
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