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Ramp up opacity with Z position
Hi there,
I have a bunch of solids placed in z space. I want to animate them like the Apple Time Machine effect.
The part that does the z-space animation is obvious. But when a layer is at position 0 in z-space I want that layer to become at 100% opacity. When it crosses the 0 point it fades out to 0% opacity. So: all the layers are behind the layer that is on 0, they are at let’s say 50% opacity. When the layers move towards the camera the opacity changes.A good example is the Dock Effect expression. But instead of scale, i want to use opacity.
Like the expression below.f = 2; //factor to increase scale by
min = 0; //distance in pixels from the center where the layer is at full scale
max = 300; //distance in pixels from the center where the layer is at 'normal' scale
c = [thisComp.width / 2, thisComp.height / 2]; //center of the composition
p = toComp(anchorPoint); //location of the current layer in the composition
d = Math.abs((p - c)[0]); //distance from the center along the x-axis
ease(d, min, max, f * value, value);
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3 Replies
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a simple one using ease could be something like this:
maxZ = 500; // this would be the z position where the layer would not be visible
ease(Math.abs(position[2]), maxZ, 0, 100, 0)if you wanted more control over the fade falloff and the amount of distance that the layer could stay at 100% opacity, then this might be better:
noFalloff = 200; // this would be the ‘zone’ where the layer would be 100%
decay = .005; // use this to adjust how quickly the layer fades in/out
d = Math.abs(position[2]);
value/Math.exp((d-noFalloff)*decay)— the later expression is is based on dan ebbert’s light falloff expression here, if you’d like a full description of what it’s doing:
https://www.motionscript.com/design-guide/falloff.html
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Hey Kevin,
Thanks for your information! I was wondering if it was possible to set the opacity of the layers behind could set to 50% opacity (like a stack of solids). The layer what’s on the zero point always is 100%, when it crosses that point towards the camera, it goes to 0%.
Again, thanks for for help!Bram
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i missed that part in you original post…
the first expression would be easiest to work in a conditional… like this:
maxZ = 500;
z = position[2];
if (z > 0) minO = 50 else minO = 0;
ease(Math.abs(z), maxZ, 0, 100, minO)you could potentially have different maxZ values too, one for where the layer starts to become more opaque and another for when the layer goes to zero opacity.
z = position[2];
if (z > 0){
minO = 50;
maxZ = 800;
}else{
minO = 0;
maxZ = -200;
}
ease(Math.abs(z), maxZ, 0, 100, minO)Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
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