Vertex attributes are removed by point attribute

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Hi

I noticed recently that if you have a vertex attribute with a given name and after you add a point attribute with the same name, the vertex attribute is removed.

Is this expected behavior? If so, why?
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kgoossens
Hi

I noticed recently that if you have a vertex attribute with a given name and after you add a point attribute with the same name, the vertex attribute is removed.

Is this expected behavior? If so, why?

I think that's to eliminate ambiguity. You should only have one attribute of a given name for any class.
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I was questioning this several times, never got satisfying answer
since there is no ambiguity, as Houdini tools usually prefer more granular attributes so vertex > point > prim > detail
and you can definitely for example still have point name and prim name and detail name at the same time, so not sure why vertices are treated differently and fight with points
Edited by tamte - Nov. 17, 2022 12:16:25
Tomas Slancik
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tamte
not sure why vertices are treated differently and fight with points

In an attempt to get started with Solaris this sentence got my attention 'And Vertex interpolation is (confusingly) equivalent to a Houdini point attribute. The interpolation method is stored as metadata on the primvar attribute.'

USD [www.sidefx.com]

One quess, if you are dealing with Solaris, is that there is at least to some degree a conflict due to USD's naming convention or standard? Houdini's legacy is obviously not an exact match to USD.
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In an attempt to get started with Solaris this sentence got my attention 'And Vertex interpolation is (confusingly) equivalent to a Houdini point attribute. The interpolation method is stored as metadata on the primvar attribute.'
this is just a confusion between USD naming and Houdini naming
Houdini | USD
vertex | FaceVarying
point | Vertex
prim | Uniform
detail | Constant

however the actual issue with point and vertex Houdini attributes clashing if named the same is older than LOPs or Solaris so it has nothing to do with it
I even think it didnt used to be that way and both vertex N and point N, vertex uv and point uv used to be allowed on the same geo at the same time, and that would make a lot of sense from the clear attribute priority rules, but someone at some point thought that only one should exist
So I'm curious what is the reason since its inconsistent as described above
Edited by tamte - Nov. 17, 2022 15:40:53
Tomas Slancik
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Method Studios, NY
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