• Adobe After Effects Expressions

  Reverse X and Y coordinates for puppet pin motion

  Posted by Tony Caver on August 3, 2012 at 10:36 pm

  Hey folks, I’m linking puppet pins to a track with motion tracking applied. The source track has mostly up and down motion, and I would like to use that vertical motion to drive a puppet pin horizontally. I’ve been searching for an expression to switch x and y…. with no luck. Optimally, a null would be linked to the source tracking data, and pins would be adjustable through the null anchor point, and X and Y would be reversed.

  Both of these expressions work by themselves but I can’t hack them together. First one attaches source motion data–Second one reverses my x and y.

  L = thisComp.layer("source");
M = L.motionTracker("Tracker 1")("Track Point 1");
fromWorld(L.toWorld(M.attachPoint*-1
) + M.attachPointOffset)

  L = thisComp.layer("Null_1");
x = (L.position-L.position.valueAtTime(L.inPoint))[1];
value + [x,0]

  Dan Ebberts replied 14 years, 1 month ago 2 Members · 3 Replies
• 3 Replies

• 

  Dan Ebberts

  August 3, 2012 at 11:29 pm

  I haven’t tested it, but it seems like this should work:

  L = thisComp.layer(“source”);
  M = L.motionTracker(“Tracker 1”)(“Track Point 1”);
  P = fromWorld(L.toWorld(M.attachPoint*-1 ) + M.attachPointOffset)
  L2 = thisComp.layer(“Null_1”);
  x = (L2.position-L2.position.valueAtTime(L2.inPoint))[1];
  P + [x,0]

  Dan
• 

  Tony Caver

  August 4, 2012 at 1:34 am

  I tried your code on my null but the puppet pin still had Y and X movement. My source (which also has the pins and motion data) has
  this:l = thisComp.layer(“Null_1”); fromWorld(l.toWorld(l.anchorPoint));

  My null has this:
  L = thisComp.layer(“Tracker-and-Pins”);
  M = L.motionTracker(“Tracker 1”)(“Track Point 1”);
  P = fromWorld(L.toWorld(M.attachPoint*-1 ) + M.attachPointOffset)
  L2 = thisComp.layer(“Null_1”);
  x = (L2.position-L2.position.valueAtTime(L2.inPoint))[1];
  P + [x,0]

  Is there a way to do this?
  Actual_X=[0] //X data variable
  Actual_Y=[1] //Y data variable

  Position=[Actual_Y, 0] //put the y data into the x dimension.
• 

  Dan Ebberts

  August 4, 2012 at 5:10 am

  I’m confident that the answer to your question is “yes”, but I don’t have a good picture of what you’re trying to do.

  Dan

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