maya xgen ass data not rendering in Houdini

[Anonymous]

Hi i'm trying to render xgen generated hair ass data in houdini but unfortunately this throws some errors. I could not find any thing about this in htoa documentation .it looks like needs some external setup besides default setting done on installation time .

Do you guys have any idea on this?

Thanks

[lee_griggs]

What are the errors? What does the log file say?

[Anonymous]

Error log looks something like this .

ropNodeError_log.txt

houdiniConsole_log.txt

[Stephen.Blair]

The ASS file has MtoA-specific shaders. So you need to add the location of the MtoA shaders (like MayaChecker) to the plugin search path.

And XGen requires Maya libraries, so you need to add some Maya folders to PATH.

For example:

https://arnoldsupport.com/2018/02/02/maxtoa-rendering-xgen-in-3ds-max/

[Anonymous]

Actually i tried this one . i added them to my system environment variable path but unfortunately did work for me.

[Stephen.Blair]

You also have to add the MtoA procedurals folder to the Procedural Search Path.

And then get an Arnold log that shows what happens when the ass file is loaded.

[Anonymous]

yes i tried that one too , but still not working

[Anonymous]

is it possible to maya xgen fur to houdini

[awu2500]

you can render xgen in houdini with arnold, only if you use all arnold node for xgen shader in maya. I have done a little test, set all the env path, export xgen to ass in maya , load in houdini, it can render perfectly with htoa in out part, but I can't render out anthing in solaris, I can't figure out why, is it not support yet?

[mark13Stefan]

Hey, I got it working by exporting xGen as USD file in Maya and in Solaris creating an ArnoldUsd Prim (via Inline USD, see below) that reads that usd file.

def ArnoldUsd "xGen"
{
    string arnold:filename = "C:/some_xgen_file.usd"
    uint arnold:id = 0
}

[awu2500]

how could you export xgen as a usd file? I tried to export xgen as a usd file with arnold or maya usd plugin, I got a very small usd file, and it can not render out anything at soloris.

[mark13Stefan]

the usd export does not expand the procedural, even with the expand procedural checkbox enabled. I think this just applies for ass export. Arnold still needs to create the curves at rendertime. In the exported usd a primitive of type "ArnoldProceduralCustom" is defined with all attributes you would have in an unexpanded ass file. In Houdini you need to have all environment variables setup so arnold can find the procedurals and plugins from Maya.
Then create a ArnoldUsd Primitive, that points to the usdfile with the xGen.

[awu2500]

thanks for the reply, I just did what you said,I think all the environment variables is setup, but I still got the " node  xgen_procedural  is not installed" error,finally I copy all the xgen dll files from mtoa to htoa, I can render xgen usd at Solaris,but saddly the hair lost all the shader, everything is purple color.please help me out.

[mark13Stefan]

You can assign a shader in Solaris and it should work. I had the same issue.

Also interesting:
If you want to change the mode to ribbon/thick/oriented you can use a "Edit Properties" LOP and add a parameter called "primvars:arnold:mode".
All properties, that have the primvar-prefix get piped through as overrides I guess.
[cid:6cd945a6-eec8-4d54-a9c7-ce6eaedef10f]

[Stephen.Blair]

---

@awu2500 wrote:

thanks for the reply, I just did what you said,I think all the environment variables is setup, but I still got the " node  xgen_procedural  is not installed" error,finally I copy all the xgen dll files from mtoa to htoa, I can render xgen usd at Solaris,but saddly the hair lost all the shader, everything is purple color.please help me out.

---

Instead of copying the dll files, set ARNOLD_PLUGIN_PATH before you start Houdini
Set it to point to the MtoA procedurals folder.

Setting the search paths in the render settings should work, but they don't and that's a bug for sure.

[awu2500]

right, I reassign the shader,it did work, but if the hair have more than one shader, I do not know how to deal with it.
and in the "Edit Properties" LOP ,you can find all the properties of arnold under the schemas,we can also use a Primitive LOP and Edit Properties LOP to load xgen ass file or arnoldUsd file instead of inline usd,that's what we do for xgen for now. it's just sometime the xgen ass file could be very large,hope it can render xgen usd perfectly at solaris someday

[awu2500]

"ARNOLD_PLUGIN_PATH" environment variable did do the job,hope they can fix the shader issue