Hi is there any way using a attributeWrangle to know the names of the children of a Primitive? I would like to Store them into a String Array.
In my .usd, each mesh primitive comes with a PBR Preview Surface material and a few textures attached. I want to know, for each mesh primitive the name of the texture file Path linked to their bound Materials.
So far I managed to get the name of the material prim linked to each mesh prim using usd_boundmaterialpath But after this I am lost The name of the texture seems to be stored in a Shader Primitive under the Material Primitive. But this primitive has a name that changes with each prim (although it always starts with "texSampler_"), so I do not know what to do. Any help is welcomed!
I think you are using VEX for things where there is a much easier solution... You should be able to find all the primitives you're interested in using a primitive pattern (https://www.sidefx.com/docs/houdini/solaris/pattern.html). Without doing any kind of checking, I would bet something like this might work: %descendants(%matfromgeo([set of geo primitives on which you're running your VEX code]))
mtucker I think you are using VEX for things where there is a much easier solution... You should be able to find all the primitives you're interested in using a primitive pattern (https://www.sidefx.com/docs/houdini/solaris/pattern.html). Without doing any kind of checking, I would bet something like this might work: %descendants(%matfromgeo([set of geo primitives on which you're running your VEX code]))
If I understood it correctly, the primitive pattern would allow me to select the shader primitives, but in my case I need to operate on the mesh primitives and extract the strings of the texture path connected to their PBR Preview Shader material (which come with the file).
My goal is assign a unique shader to all my mesh prims and have the texture variate per primitive. Like a per primitive material override in mantra. Therefore I need to find a way to know the texture paths linked to each mesh prim. With usd_boundmaterialpath I can locate the material prim of a mesh prim, but after this I get stuck.
PaoloGiandoso And to answer your original question, no, there is not currently a VEX function to get the children/descendants of a primitive.
So weird that there is a find parent but not a find descendant function .
PaoloGiandoso f I understood it correctly, the primitive pattern would allow me to select the shader primitives,
Correct. From there you can traverse the ancestors to get back to the mesh primitives (or their parent if that's where the material binding has been authored). See attached .hip file.
Another way is to use Python LOP and use the USD API directly, instead of the Wrangle and the VEX. See the attached .hip file too.
PaoloGiandoso So weird that there is a find parent but not a find descendant function
Good news is that it has been already added to the future 19.5 branch.
rafal Another way is to use Python LOP and use the USD API directly, instead of the Wrangle and the VEX. See the attached .hip file too.
Indeed python has more options than vex. However, when working with a big stage and iterating around a lot of primitves (200k, for example), you start to see that vex significantly faster than python. So beware of the performance hit.
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