Linking position to mask path?

[Navarro Parker]

I know I can copy and paste a Mask Path to a layer's Position and vice versa.

But is there a way to link them live with an expression?  I think I'm running into a problem with too many dimensions in an array -- I'm trying to link a Light's 3D position into a 2D Mask Shape (for Particular).   I can copy and paste the motion path & mask shape between them just fine, but pickwhipping gives me an error.

[Dan Ebberts]

Not directly, but there may be a work-around, depending on what you're trying to do. If you paste the path into the position property of a null, AE creates a smooth 2-second animation. You can like to the null's position and use a positon expression with the light (using valueAtTime()) to traverse the path on any timescale you want - stop, back up, etc. If what you're looking for is a live link between the path and the light though, then this doesn't help.

A script has access to all the mask stuff, so depending on exactly what you're trying to do, you could use a little helper script to update your light position keyframes after you edit the path.

Dan

[Navarro Parker]

Thanks for the info.  I'll post a script request at AEnhancers.com

[Navarro Parker]

Does CS5 handle this any differently?

[Dan Ebberts]

No - sorry.

Dan

[SonyGreen]

I don't suppose this has changed since 2010? Thank you!

[Dan Ebberts]

No, it hasn't.

Dan

[SonyGreen]

Ah, too bad. Well, thank you very much for letting me know!

[JohnyFive]

Navarro, this makes me think of Mathias Mohl's Tracker2Mask Script, i'm wondering if that would work for it.  Tracker2Mask - aescripts + aeplugins - aescripts.com

But i'm not sure.