[Chris Jeffries]

Just wanted to say thanks for the help also – was just what the doctor ordered! 😀

[Chris Jeffries]

First, thanks for the tutorial. Much appreciated. Very cool technique with the light path.

Second, the purpose of this post is to address an issue I’ve encountered while working through the process. After setting the expression for the particle emitter, I wasn’t seeing the position of the particle emitter change in response to changes made to the position of the motion path layer. My fix follows.

For “Position XY” expression:
temp = thisComp.layer("Null 1").position.valueAtTime(time);
[temp[0], temp[1]]

For “Position Z” expression:
temp = thisComp.layer("Null 1").position.valueAtTime(time);
temp[2]

The key change to note is that the valueAtTime(0) parameter has changed to valueAtTime(time) in order to keep the emitter position in parity with the motion path.

Additionally, I found no problem with simply using a Null as my position reference rather than the light as indicated in the tutorial. You’ll notice this change reflected in my modification of the code: layer(“Null 1”) (mine) vs. layer(“Motion Path 1”) (original).

Hope this is of use!

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Caltd
“Redefining the future history of cyborganics since 1979”