The reason is that the first object becomes invalid once you run addProperty again. You can add the properties back to back like in version 2, but you would need to assign them to variables afterwards like in version 3, to be able to access any attributes for them.

VERSION 1

var vppath = curLayer.Effects.addProperty("VP-Path");

vppath.property("Azimuth").expression = ("50");

var vp = curLayer.Effects.addProperty("Virtual Projector");

vp.property("Azimuth").expression = ("50");

This works because you are changing a value to a valid effect property immediately after creating each effect.

VERSION 2

var vppath = curLayer.Effects.addProperty("VP-Path");

var vp = curLayer.Effects.addProperty("Virtual Projector");

vp.property("Azimuth").expression = ("50");

vppath.property("Azimuth").expression = ("50");

vppath becomes invalid the second you add another property (vp), at which point you cannot change something that's invalid. You can check if a variable is valid by running:

vppath.isValid;

vp.isValid;

Doing this though, should work.

VERSION 3

//Create effects

curLayer.Effects.addProperty("VP-Path");

curLayer.Effects.addProperty("Virtual Projector");

//Assign effects variables

var vppath = curLayer.property("ADBE Effect Parade").property("VP-Path");

var vp = curLayer.property("ADBE Effect Parade").property("Virtual Projector");

//Change properties

vp.property("Azimuth").expression = ("50");

vppath.property("Azimuth").expression = ("50");

------

David Torno

Visual Effects Artist and Supervisor

http://www.ghosttownmedia.com

E: david@ghosttownmedia.com

O: 213.739.2290

C: 818.391.6060

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On Jan 19, 2014, at 2:01 PM, Drew Gilmore wrote:

Thanks yeah, now that I poke around it's clearly something else I'm doing wrong... I think I have it working. But now I'm curious. Why does this work:

var vppath = curLayer.Effects.addProperty("VP-Path");

vppath.property("Azimuth").expression = ("50");

var vp = curLayer.Effects.addProperty("Virtual Projector");

vp.property("Azimuth").expression = ("50");

But this doesn't:

var vppath = curLayer.Effects.addProperty("VP-Path");

var vp = curLayer.Effects.addProperty("Virtual Projector");

vp.property("Azimuth").expression = ("50");

vppath.property("Azimuth").expression = ("50");

(FWIW, VP-Path is the custom effect, Virtual Projector is a plugin effect.)

Thanks,

Drew