Hi,

currently I do a lot of Glas Products with stuff inside and I´m breaking my head with this! Is there a way to create object, attribute/polygon and material masks or RGB Mattes through Glas preferably without Cryptomatte? (for example masking a goldfish inside a glas bowl)


Thanks in advance and all the best
Christian

Hi again,

I found the fish bowl test scene from inside the Arnold Render documentation. I quickly created a super basic Lop Scene out of it and applied a float attribute for the the fin´s of the fish for a masking aov. The big question is, how can I make the Mask visible behind Glas and Water? Is it possible to use Attributes with LPE´s? (HIP File is attached)

all the best
Christian

hi,
Did you get any solution for this?

vinayfx123
hi,
Did you get any solution for this?

Hi,

yes I did just recently! There´s a new feature of H21 called Utility Path Expression.
With it you can make Cryptomatte, Attributes or Karma AOV´s consider Refractions and Reflections in a controllable LPE like way.

It works like this:

- assign RGB through Attributes or whatever technique you like
- go to the karmarendersettings LOP -> Tab:Image Output -> Extra Render Vars -> plus Icon -> call your AOV, Attribute ect -> use the source type Primvar or RAW (LPE doesnt work).
- or if you click the dropdown under Name -> choose the preset you like that is not LPE -> You can assign Cryptomatte Object or Cryptomatte Material for example
- then under Utility Data Expression type something similar to this CT*. for it to consider transparency or like this C.*<RG>*. to consider reflections as well. I´m still new to LPE, so you might want to try a combination that works for you.

best
Christian