Hi,

I would like to render sequences and wedges with Arnold using PDG/TOP.

My current setup uses a ROP Fetch node that points to the out/arnold node. I plug-in the rest of my TOP network (wedges, …) as input to that ROP Fetch node.

This renders the correct sequence of images, although the shaders are missing (my geometry is all pink).

I am using Arnold's Standard Surface Shader in SHOP, which I assign to my geometry.

I read online that SHOP was deprecated but can't figure out how to define an Arnold shader without SHOP.

Any suggestions? Is there another way to render with Arnold using PDG than using a ROP Fetch node?

Thanks!

This sounds more like a shader issue than a PDG issue. I’ve pointed your question at our rendering folks, but with SIGGRAPH on our door steps please expect some delays in our reply.

Houdini is backwards compatible and still supports SHOPs in older setups. So if you still have the Arnold's Standard Surface Shader SHOP, it should work fine.

Ultimately, it's up to the Arnold's ROP to interpret the shader networks (be it SHOPs or VOPs) and translate it to a format consumable by Arnold renderer. It may be worthwhile to ask on Arnold's forum about it.

It looks like i ran in the very same issue. Is this actually an issue? I made a simple testscene with a wedge, a ropgeometry and a ropfetch. The material is set by a material node right in the geo-node. THe shader lives in “shop/arnold_vopnet1” The arnold rop is rendering fine by itself but if the render is triggered by the ropfetch the shaders get lost. The wedge is working fine though. I don't seam to find an answer in the arnold forum either. Any direction towards a solution is very much appreciated.

THANKS!

Could you kindly post something on the Arnold forum, in that case? We’ll raise this as well with them whenever we get to meet. If you could upload a reference file, we can potentially work with them to correct the issue. Note however this may take a while, as it requires coordination between our two companies.

I have problems too triggering an Arnold ROP via the ROP Fetch inside the TOP Network.

Could you please have a look at the scene file “Arnold-PDG-Test-2.hiplc”?

Project file:
https://1drv.ms/u/s [1drv.ms]!Aisf-Kb35NH2qQGDiQUaXSz70ONA?e=UyLvr6

Any ideas what's going wrong here? Maybe it's just me and the ROP Fetch needs some additional parms?

Thanks in advance,
Andreas

Same problem happening here, just installed htoa and any scene with an arnold shader in it prevents PDG from launching instances. It's like hython doesn't see the arnold plugin or something. Is there a separate environment file for hython somewhere that needs to have the plugin path added to it?

Edit: I should add that this happens whether an arnold ROP is being called or not -- any kind of ropfetch or other TOP that spawns hython instances breaks with the errors below, if an arnold shader is present in the scene:

Well, of course after 6 hours trying to diagnose this it only takes one new search to find an answer:

https://www.sidefx.com/forum/topic/77814/?page=1#post-340670 [www.sidefx.com]


Hopefully that makes it appear a little higher up in the search results for someone else.

Just to recap what was said here. The solution is in the localcheduler node that is in the top net.
Go to the "Job Parms" tab, find "unset variables" and write HOUDINI_PATH.
Also, if you are loading Arnold from a JSON file as opposed to from Houdini environment, untick "skip loading Packages".