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Wiggling the result of an expression
I have a series of photos arranged in 3D space, and I have a NULL which moves amoungst these.
I have used an expression on a camera position to follow the NULL which looks like this:
X = 1100 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[0] * 0.3);
Y = 800 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[1] * 0.3);
Z = thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.1)[2] – 600;
[X,Y,Z];This works fine, but now I would like to add a wiggle to my position, I tried this:
X = 1100 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[0] * 0.3);
Y = 800 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[1] * 0.3);
Z = thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.1)[2] – 600;
[X,Y,Z];
wiggle(0.5,40);But this doesn’t work, it wiggles, but no longer follows my NULL.
I know I could wiggle my NULL but I am using that also as a reference to the focus point in depth of field, so if the NULL were to move away from the picture it would become out of focus.
What am I missing here?
Thanks
Matt
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5 Replies
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Hi Matt, I added a second NULL, put the wiggle expression on it
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i can’t test this right now (rendering), but i believe something like this should work:
X = 1100 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[0] * 0.3);
Y = 800 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[1] * 0.3);
Z = thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.1)[2] – 600;
[X,Y,Z] + wiggle(0.5,40);just adding the wiggle value to the original expression value…
Kevin Camp
Designer – KCPQ, KMYQ & KRCW -
It works, much better solution than mine. So simple…
Go for it Matt.
Cheers
ninguem
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[moldyboot] “i can’t test this right now (rendering), but i believe something like this should work:
X = 1100 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[0] * 0.3);
Y = 800 – (thisComp.layer(“Null 1”).transform.position.valueAtTime(time – 0.3)[1] * 0.3);
Z = thisComp.layer(“Null 1″).transform.position.valueAtTime(time – 0.1)[2] – 600;
[X,Y,Z] + wiggle(0.5,40);just adding the wiggle value to the original expression value…”
The wiggle() function does not return the difference between the original value and the wiggled value, it only returns the wiggled value. So if the original value of the property that wiggle(.5, 40) is applied to is [360,240,0] the values that wiggle(.5, 40) will return will vary from [320, 200, -40] to [400, 280, 40]. To instead retrieve the difference from the initial value (values ranging between [-40, -40, -40] and [40, 40, 40]) you need to subtract that original value from your wiggle(0.5, 40) value:
X = 1100 - (thisComp.layer("Null 1").transform.position.valueAtTime(time - 0.3)[0] * 0.3);
Y = 800 - (thisComp.layer("Null 1").transform.position.valueAtTime(time - 0.3)[1] * 0.3);
Z = thisComp.layer("Null 1").transform.position.valueAtTime(time - 0.1)[2] - 600;
[X,Y,Z] + (wiggle(0.5,40) - value);
Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA -
excellent catch, thanks darby
Kevin Camp
Designer – KCPQ, KMYQ & KRCW
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