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Paolo Giandoso avatar image
Paolo Giandoso asked ·

How can I read houdini geometry attributes from alembic files in Maya Arnold?

Hi

When using Arnold for Maya Is it possible to read geometry attributes from a alembic file created in Houdini?

I know attributes must be promoted to vertex and that you can read the Cd attribute (because it is automatically converted in maya to a Color Set). The user data color can read it.

But I have tried to read float and vector attributes using the User Data Float and User Data Vector and Arnold does not seem to be able to read them. Is the only way to save attributes as Color Sets?

For instance I exported a .abc geometry file from houdini with a vertex float attribute called "infect" with range 0 t 1 and I wanted to plug it in the Roughness slot of a aiStandard Surface. How can I do it correctly?

Many thanks


mtoahoudinicolorattributes
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rachid Hadj Abderrahmane avatar image
rachid Hadj Abderrahmane answered ·

Yes you can read any attribute, import your alembic file as GPU Cache and not Alembic Cache

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Paolo Giandoso avatar image Paolo Giandoso ·

Awesome! Can I ask what is the workflow for reading the attributes when using GPU caches?

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rachid Hadj Abderrahmane avatar image
rachid Hadj Abderrahmane answered ·

It depend on attribute you exported, but in general
UserDataColor or UserDataRgb for Cd
UserDataFloat for attribute that have float value
UserDataInt for attribute with single (integer value)
UserDataVec2 for uv

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Paolo Giandoso avatar image Paolo Giandoso ·

Thanks!

Side question: Is there a way to know from the GPU cachce node which are the names of the geometry attributes saved in the file?

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rachid Hadj Abderrahmane avatar image rachid Hadj Abderrahmane Paolo Giandoso ·

That will be great! unfortunately no, you have to remember all the attributes you add

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