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hold an expression at it's last value

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 hold an expression at it's last value on Dec 5, 2016 at 10:50:47 am

hey all you expression wizards ☺

I wish to figure out how to stop an expression at it's ending value: say I have a rotation of a layer set to time*30 and I want to create a checkbox control to hold it (and continue) every time I click it.

so I have this:
if (effect("Checkbox Control")("Checkbox")==1) time*30 else ?;

what should I put after the else the makes it "stop at current time" so I can toggle this time expression on and off and keep my current position when I freeze it?

thank you

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials

 Re: hold an expression at it's last valueon Dec 5, 2016 at 5:18:37 pm

Something like this, probably:

``` chkBx = effect("Checkbox Control")("Checkbox"); n = 0; if (chkBx.numKeys > 0){ n = chkBx.nearestKey(time).index; if (chkBx.key(n).time > time) n--; } t = 0; curTime = time; if (n > 0){ for (i = n; i > 0; i--){ if (chkBx.key(i).value > 0){ t += (curTime - chkBx.key(i).time); } curTime = chkBx.key(i).time; } if ((curTime > 0) && (chkBx.key(1).value > 0)) t += curTime; }else{ if (chkBx.value > 0) t = time; } t*30 ```

Dan

 Re: hold an expression at it's last valueon Dec 5, 2016 at 8:52:29 pm

Thank you Dan. it works and I will keep it near. I was thinking this could be much simpler so I could tweak it to other manipulations as well - for example wiggle. here I was thinking that instead of my "?" there's only a few letters of codes and that's it. I can't really get my head around this but blindly copy pasting it. guess this was heavy stuff.

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials