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Activity Forums Adobe After Effects Expressions Techniques for Lightening expression computations?

  • Techniques for Lightening expression computations?

    Posted by Alex Printz on July 23, 2018 at 3:16 pm

    Hey all, I’ve been wondering lately what are some of techniques for lightening the expressions you use? Right now I’m working on a large comp, maybe 20000×3500 pixels, featuring a vehicle driving across a scene with a lot of expressions running for various features. My workstation has been lagging horribly, so I’ve been thinking and looking at ways to reduce expression load. One that I liked a lot is something I’ve seen Dan using checking the in/outPoints, which I made universal below:

    if (time < inPoint || time > outPoint){ value; }
    else{
    //BEGIN EXPRESSION HERE

    }

    Does anyone have any other ideas? I’ve gone through every expression and stripped out anything non-essential, and I’m also using EasyBake to bake my expression values into keys (along with good workflow like lower quality, no aliasing, isolate views, etc.), but any other ideas specifically for expressions would be valuable. Thanks!

    Alex Printz
    Mograph Designer

    Kalleheikki Kannisto replied 7 years, 9 months ago 2 Members · 3 Replies
  • 3 Replies
  • Kalleheikki Kannisto

    July 24, 2018 at 5:54 am

    If you have a vehicle driving across the scene with expressions, you likely have one or more FOR or WHILE loops that check backwards through each frame for features like acceleration. That’s going to grind AE down to a half after a while. There’s not a hell of a lot you can do about those except bake them into keyframes. Or split them into several pieces with camera cuts in between so as to shorten the time the loops have to look backwards. On the plus side, the edit will look more interesting with camera cuts.

    Kalleheikki Kannisto
    Senior Graphic Designer

  • Alex Printz

    July 24, 2018 at 2:16 pm

    Thanks Kalleheikki, but there are no acceleration expressions present. There are collision detection expressions (that are limited to the in/out points, so only when the effect is required is it running), and there are some cross-comp links that might be dragging everything down.

    There are also some recursive scripts (check shapelayer index, multiple offset by index number, etc.) for some radar assets I need, but I have looped them as precomps so they ought to be only cycling the same ~6 frames, so they should only need to be calculated once.

    Thanks for the suggestions though. Any other scripting efficiency stuff you can think of I’d love to learn.

    Alex Printz
    Mograph Designer

  • Kalleheikki Kannisto

    July 25, 2018 at 5:15 pm

    For some really expression-heavy projects I have duplicated the layers that have expressions and either converted the expression to keyframes or prerendered the layers. Then hide the originals. That way nothing has to be calculated live but I retain the option of going back and modifying the expressions if need be.

    Kalleheikki Kannisto
    Senior Graphic Designer

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