Adding/exposing hidden attributes to ArnoldAttributes node

[Riccardo Cecchinato]

Hello!

I was wonderind if it is possible to add/expose custom or hidden attributes to the ArnoldAttributes node?

I would like to expose the diffuseSample and specularSample controls, to selectively increase the indirect samples on specific objects of my scene, but I am not sure how to do it, or if it is even possible. 

I know that per-object indirect sampling parameters have been hidden/removed from Arnold shaders since a while, but maybe it is possible to force them in Gaffer through  the ArnoldAttributes node?

 I am on Gaffer 1.5.2 and Arnold 7.3.5.

Thank you as usual for your invaluable help,

Riccardo

[John Haddon]

Hi Riccardo,

I'm not aware of Arnold having any per-object attributes to control diffuse and/or specular sampling. Can you point us to the Arnold documentation for the features you're thinking of?

Cheers...

John

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[Riccardo Cecchinato]

Hello John, 

thanks for the quick reply!

This operation is possible on the Hair shader for example :

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_core_ac_standard_hair_html ("Extra Samples", at the very end of the page).

The parameter ("parameters.extra_samples)" is well exposed in Gaffer too, for the StandardHair shader, but not for the other shaders/meshes.

I was wondering , is this because the parameters is hidden, and if so, how would it be possible to re-expose it?

Or is the feature not present at all, a-part for the Hair shader?

I hope this issue does not overrun your area of expertise, considering it is more of an Arnold-related question.

Thanks again for the great support,

R

[John Haddon]

As a general rule, we expose all the parameters of the Arnold shaders in the UI, hence why you can access `standard_hair.extra_samples`. But there aren't any sampling parameters on `standard_surface`, which is why you don't see any in Gaffer. You can get a list of all parameters for a particular shader directly from Arnold itself using `kick -info <shadername>`. If you see a parameter there that isn't exposed in Gaffer then by all means let us know. But if you don't see a parameter there, there's not really anything we can do about it...

To view this discussion visit https://groups.google.com/d/msgid/gaffer-dev/4af30c82-2250-40d7-96ad-16bb0d913359n%40googlegroups.com.

[Riccardo Cecchinato]

Hello John!

Makes total sense, and it seems like there is none - as you said.

Thanks again for double checking for me,

Riccardo