Renderman Aov

[iamjaideep80]

Hi Everybody.........

i am trying to use Arbitrary Output Variables in Renderman. I m getting the default layers such as, P N s t du dv......... But I want to use my own layers, such as diffuse, Reflection, Specular etc.

Can it be done with with Renderman shaders written with VEX Networks,

or I have to write sl files.

Pz tell me how to do it.

Thanking in advance.

Jaideep

[Jason]

\Can it be done with with Renderman shaders written with VEX Networks,

or I have to write sl files.

20558[/snapback]

Hi there,

You can do it very easily in VOPs - the secret is to use the Parameter VOP with its "Export" parameter switched on. Wire the data you wish to export into the input on the Parameter VOP. You may also want to hide the parameter from the shader parameters by clicking the "Hidden" parameter on the Parameter VOP.

I'm sure it must talk about this in the Parameter VOP help card too.

Hope this helps,

Jason

PS. This is the same technique used for Mantra shaders.

[iamjaideep80]

I think i got the Answer.

We just have to add Parameter Vop, and choose to Export it.

Feed into it, diffrent layer information, such as diffuse, reflection and give it a name. And use the same name in Render AOV.

But I still have a question. Should we use Diffrent Lighting Models for each layer(Changing thier parameters to output perticular pass), Or should seperate it using diffuse, specular, ambient functions provided by Renderman.

Will the second approch take less time to render ?

Plz Explain.............

Thanking in advance ......

Jaideep

[iamjaideep80]

Hi Jason......

I think we were writing at the same time. But i was littile late.

Thanks for ur Reply.......

Jaideep

[Jason]

Hey Jaideep,

It's almost certainly faster to output AOVs than seperate passes because there is a whole bunch of stuff Renderman must do which is totally seperate to actually executing the shader code - things like Hiding, Dicing, etc - just read up on Reyes renderer architecture and you'll see. You can save on all this time by just getting the shader to do more work and forgo multiple passes. The shader execution time is relatively small cost if the shaders are fairly simple.

Jason