Creating my custom AOV in Maya using an Houdini created attribute

[square-zero-one]

I've setup an object space pref property in houdini and cached out my objects.

I would like to create an AOV in maya to read this property.

How to setup it up?

I've tried the following but couldn't make it work.

Thank you

Johnny

[Anonymous]

Take a look here
https://forums.autodesk.com/t5/maya-shading-lighting-and/pref-pass-in-arnold/td-p/6937341

[square-zero-one]

Hi @rachid Hadj Abderrahmane

Thank you for the link.

I had a look at it before, but I want to have it coming from Houdini and also to use any other property, not just Pref.

What I would like to know how to properly read a property that it's in the mesh and display it using an AOV

Thank you

Johnny

[Stephen.Blair]

I do wonder about using the the same parameter name Pref that Arnold uses. Can you try with a different name?

[square-zero-one]

Maybe Im doing something wrong? What is the way to load geometry attributes into an AOV? I changed the name and still got black ( changed but AOV name and Attribute ) .

Are this steps right?

1. Create custom AOV
2. Choose its DATA type
3. On the AOV attributes , set Custom AOV, Shader to aiWriteFloat
4. Set its input as aiUserDataFloat
5. Render it

Keep getting black, not sure if Im setting it up correctly

Thank you

[Stephen.Blair]

You don't actually need the aiWriteFloat, you could connect the user data shader directly. But there's no harm in doing it that way.

Your setup sounds correct. It should work like that:

So...is the user data actually there?

I would export an ASS file (with Expand Procedurals enabled) and check

[Anonymous]

Here how I do it, simply connect aiStateVector (Shading Point in World-Space: P ) or Shading Point in Object-Space: Po) to aiWriteVector, then force the connection by manually connecting the out Color to custom AOV Shader

[square-zero-one]

I've tried it now and this work, but it's the native arnold attributes I would like to get my own attributes read, anyway this is a great tip , Thank you

[square-zero-one]

Im now trying to load just a Cd property out of houdini into a normal shader not even into an AOV, I can't seen to get anything.

https://docs.arnoldrenderer.com/display/A5AFHUG/User+Data

Is there any basic workflow Im missing?

Im pretty sure my cache has the attribute as I can see them in Houdini after unpacking...

Thank you

[Anonymous]

You can read any attributes from Houdini, if you import the alembic file via Cache /GPU cache=> Import.

[Stephen.Blair]

Cd worked for me.

I loaded the abc with an aiStandin in Maya

[square-zero-one]

Yeap that was the trick!!!!!

I was just importing the alembic, not gpu cache or StandIn

It all working for me! Thank you so much Stephen and Rachid !

[square-zero-one]

And even better, if I drop the built in Pref Aov, it just loads it correctly without any wiring !!!

Thank you both for all the help

[Anonymous]

Glad you were able to solve your problem!