Hey Tom !
Yeah this is an historical bug with the blur and how it acts with (premultiplied) alpha. Try a compo 3D box and a blur over it, and you'll see the results are vastly different with or without an alpha layer:
Blur on image without alpha -
![](//forum.smode.fr/uploads/default/original/1X/253d53d44dd959651b61ec4caace74e3e637a1f6.jpg)
Blur on image with alpha -
![](//forum.smode.fr/uploads/default/original/1X/d0cf8c98d40145a4921fb450d2e5bea894e407b3.jpg)
It's too bad cause the DOF always worked but has been unused because of this artefact. Good to see some feedback on it ! Maybe the historical Blur vs. Alpha bug will get prioritized a bit more thanks to this ![:slight_smile: :slight_smile:](//forum.smode.fr/images/emoji/google/slight_smile.png?v=3)
There is an internal tool that exists to do that, but is not available to the public due to lack of time to develop it, called the Instantiator. It allows you to create instances of a shared element over time, and would eventually allow to to interpolate some of the (exposed or not) parameters of the different instances over their instance indices.
If you have examples of tools or plugins in other software that allow you to do that, please share them ! If you have scenarios / use cases for such a tool, please share them too.
Perhaps it would be a good occasion to bring the Instantiator to the public !
There is no tool like the pickwhip, but you could do that today with groups (although I agree, it's not a direct layer to layer placement dependency).
What could exist for that is a LUA link modifier. You could create a local link (modified by a Script Link Modifier) inside your compo, obtaining the equivalent of MAX wire parameters. What we have (still internal because of lack of demand on it) is a LUA script tool, working with local exposed parameters (which also does what you ask here).