I'm trying to extract some AOVs from particles that are partially transparent and constant shaded. For mattes, for example.

Unfortunately it seems that AOVs are multiplied by the opacity no matter what... which seems wrong and difficult to work with, since... they're AOVs and theoretically should be able to do anything.

Maybe I'm getting old but I seem to remember doing this easily enough in Mantra.

So I now want to try the LPE approach and make an AOV for each subset of my particles' shader emission. Ideally a prim for each particle group, and tag them with a LPE tag and make a different render var for each.

Does that work?

Hey there, I have exactly the same problem. I need a AOV where my unlit mat particles with a translucency of 1 show up. How would I e.g. get a velocity AOV?
Thanks!

Use an LPETag LOP to add a tag to the various prims you want included in the AOV.
Then add an LPE AOV with the source name set to

dagoose
Hey there, I have exactly the same problem. I need a AOV where my unlit mat particles with a translucency of 1 show up. How would I e.g. get a velocity AOV?
Thanks!

Unfortunately I don't think you can get a velocity AOV from unlit particles.
As far as I know your best bet would be to render a separate pass with the transmission set to 0 and opacity at 1. Then you can add an AOV to output the velocities primvar.