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Activity Forums Adobe After Effects Expressions complex task, perhaps an expression can solve?

  • complex task, perhaps an expression can solve?

    Posted by Guy on September 22, 2005 at 3:06 am

    I have multiple square layers arranged in a non-uniform, patchwork grid.

    I would like to animate the opacity of these layers based on the the luminance of another layer (source) at the point that each
    sqaure sits.

    So my finished comp basically would look like the source luminance layer, but in the pattern of the grid I have layed out.

    basically the laters would “cascade” in opacity based on the luminance if the source layer.

    can do?

    Roland R. kahlenberg replied 19 years, 4 months ago 3 Members · 6 Replies
  • 6 Replies
  • Mylenium

    September 22, 2005 at 6:18 am

    If you are willing to invest in third party plugins, it can be done, if not, there is no way of doing it with just plain AE. It’s still gonna be a tough one since the expression would need to calculate the luminance with respect to how the layers overlap.

    Mylenium

    [Pour Myl

  • Roland R. kahlenberg

    September 22, 2005 at 6:29 am

    Expressions can’t read a layer’s luminance values. But Particle Playground can. You can use PP’s Grid property to create the grid for you, using a Layer Map of the videos. This one’s achievable but a lot of planning and tweaking are required if you are particular where a specific layer sits within the grid.

    To get each layer within the grid to react to the luminance level of a source layer, you’ll need to create a Property Mapper.

    I suggest that you take a look at my Fun in Particle Playland COW tutorial to get you started on working with PP’ Grid, creating and controlling Layer Maps and setting up a Property Mapper.

    HTH
    Roland Kahlenberg
    broadcastGEMs
    customizable animated backdrops with Adobe After Effects project files

  • Guy

    September 22, 2005 at 1:55 pm

    for this task I would be willing to invest. Any suggestions?

    thanks!

  • Guy

    September 22, 2005 at 4:24 pm

    yes, I read the tutorial, you are spot on. It will take ALOT of setup, but the results are not a compromise, exactly what I am looking for.

    thanks

  • Guy

    September 22, 2005 at 9:03 pm

    hey Roland, in your tutorial,is there a way to get the numbers to stop, so the particle is only sampled once in time?

  • Roland R. kahlenberg

    September 23, 2005 at 12:21 pm

    [Guy] “hey Roland, in your tutorial,is there a way to get the numbers to stop, so the particle is only sampled once in time?”

    Good Q! I fooled around a little but I can’t seem to get it to behave – sorry. It sounds achievable but somehow I’m not getting it. Let me kniow if you do manage to solve it.

    Your best bet is to make a precomp, create a duplicate, mask off an area and use Time Remap to freeze the masked off area.

    Good Luck
    Roland Kahlenberg
    broadcastGEMs
    cusotmizable animated backdrops with Adobe After Effects project files

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