Forums Technical Discussion need help for chop: keep value

need help for chop: keep value

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luoqiulin
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here are two channels, named source and reference, i want the source channel keep changing value if the reference channel is upper than 0,
and keep value if the reference is below 0.
attached jpg shows what i want
how can i do this?

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chop.jpg (101.5 KB)

https://vimeo.com/user3971456/videos [vimeo.com]
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malexander
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The Hold CHOP does exactly what you want. You'll need to separate the channels, feed the one you want to hold into input #1, and the reference channel into input #2.
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luoqiulin
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twod
The Hold CHOP does exactly what you want. You'll need to separate the channels, feed the one you want to hold into input #1, and the reference channel into input #2.

thank you Twod, I've tried hold, it seems hold values to minimum and maximum, like some kind of clamp.
i think i need hold when the reference is below 0 only, am i set the Hold wrong? or need any more after Hold?

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chop02.jpg (93.7 KB)

https://vimeo.com/user3971456/videos [vimeo.com]
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circusmonkey
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I believe icmin and icmax work on a channel you can find the min and max and extract the values out into sops as an attribute.

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sparkChan
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you can use Expression CHOP, the first input of expression chop is your reference curve, and the second input is the source, and then in the Expression 1 field, typing the expression:if(ic(0,0,$I)>0, ic(1,0,$I), oc(0, $I-1)). I think this is what you want.
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