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Vegas Effect – backwards?
I’m using the vegas effect on an open path. I have an expression controlling the “rotation” property. The expression uses time as a base value:
time * x, where x is a number between 250 and 1000.
Sometimes when I ram preview, the vegas effect runs backwards (following the path from the end to the start). I tried multiplying my expression by -1, and that worked for a while. Then, some of the layers started working backwards again.
What am I missing here? Obviously I could just animate each layer by hand, but I’m trying to avoid that. Also, I have trouble putting a problem down until I understand it. Any ideas?
Nate Hanson
Pilothouse Films -
3 Replies
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Is it perhaps a case of the wagonwheel spinning backwards ?
https://en.wikipedia.org/wiki/Wagon-wheel_effect
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Wagon-wheel effect: that was my third or fourth guess…but I slowed it way down and the problem persists. And it will change directions (occasionally) on a new ram preview, even when I haven’t modified any setting remotely related to the vegas effect.
Maybe the adaptive resolution setting is guessing wrong from frame to frame? Maybe it has to do with random seeding? I unchecked the Random phase box. I’m stumped.
Nate Hanson
Pilothouse Films -
I think that Filip is on to something here.
Setting a rotation value to 1000*time means that you’re rotating by a blazing speed of nearly 3 whole revolutions (1080 degrees) each second.
The motion that you’re seeing (no matter what motion you’re seeing) is certainly an artifact of the temporal sampling of this wicked-fast stream of “lights”.
I think that you’ll get much more sensible results if you set rotation to some much smaller multiple of time. Then you won’t be playing a guessing game or doing some complex math involving modulus operators.
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Todd Kopriva, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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