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Activity Forums Adobe After Effects First post. Could use some expression tips.

  • First post. Could use some expression tips.

    Posted by Randy Davis on March 5, 2017 at 11:20 am

    Greeting:

    I am studying AE and am pretty overwhelmed with so much to learn. Currently I am working on a project in which I would like a near invisible layer to slowly fade in and out over time. This will be a ghostly image in the background of a composition. Instead of key framing this, I know it is very easy to do with a random expression. The problem is that I am just now beginning to learn about expressions and do not yet possess the knowledge to do this myself. Could someone give me a hand please.

    Much appreciated

    Randy

    Randy Davis replied 9 years, 2 months ago 3 Members · 4 Replies
  • 4 Replies
  • Mike Sevigny

    March 5, 2017 at 5:16 pm

    I think the wiggle() expression is what you’re looking for.

    Expressions can be overwhelming at first but it’s worth it the moment you can wheeled their power
    Spend some time on Dan Ebberts’ website (https://www.motionscript.com/) and check out some of the COW expression video tutorials.
    The pros on this forum are quick to help, post your questions as you go.

    Mike Sevigny
    https://www.torusmedialabs.com

  • Randy Davis

    March 5, 2017 at 6:07 pm

    Thanks for the link to Dan’s site, I’ll be sure to check it out. Wiggle will not work in it’s pure form as I would like the opacity to change slowly, over a couple of seconds even. Think of a ghostly image slowing fading in and out of view.

  • Walter Soyka

    March 6, 2017 at 10:37 am

    [Randy Davis] “Wiggle will not work in it’s pure form as I would like the opacity to change slowly, over a couple of seconds even. Think of a ghostly image slowing fading in and out of view.”

    You can wiggle() slowly.

    Wiggle takes a few parameters (called “arguments” in Javascript); the first is frequency, or number of wiggles per second. Setting this to a fractional value gives you a very slow wiggle.

    Walter Soyka
    Designer & Mad Scientist at Keen Live [link]
    Motion Graphics, Widescreen Events, Presentation Design, and Consulting
    @keenlive   |   RenderBreak [blog]   |   Profile [LinkedIn]

  • Randy Davis

    March 7, 2017 at 2:16 am

    So I assign a random variable, maybe controlled by a slider, in the first line giving a fractional value, and then use that variable in the wiggle expression on the second line. Thank you.

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