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How to render VDB volumes in Solaris

Message 1 of 8
3450 Views, 7 Replies

How to render VDB volumes in Solaris

Hi all, just got Houdini 18.9.416 and HtoA 5.2.1 working.

Saw this in the new features list:

"Volume rendering with support for OpenVDB and particles."

I know this may not directly apply to the Arnold USD delegate, but looking here it says VDB assets are supported.

I have a Solaris scene setup that imports a VDB as a USD volume with fieldName = density. The VDB is rendering using Houdini GL with Solaris, but nothing with Arnold. I've assigned an Arnold Standard Volume shader to the volume and made sure I can see a simple sphere in Arnold so the renderer is working for geo.

I also get this error when Arnold first tries to render the VDB volume:

[HdArnold] Cannot load _htoa_pygeo library required for volume rendering in Solaris

I've attached my simple HIP file:

Any got VDB volumes to render through Arnold in Solaris?



Labels (4)
Message 2 of 8
in reply to: Anonymous

Hi Geordie,

The Arnold Render Delegate uses a Houdini library to run Houdini specific code, and the warning you are seeing is an indication that it can't find the library with the functions required.

I assume this would happen due to an incorrect environment, could you please share your houdini.env and your Houdini env info (go to help, about Houdini, press show details and use save to export everything)?



Message 3 of 8
in reply to: Anonymous


im having the same problem. Using the package json files to setup the environment, and its loading packages inside packages. But disabled all of that for test.

the only thing in the houdini.env at the moment is straight from the installation page:


PATH = "$PATH;C:/htoa/htoa-5.4.0_r1db094a_houdini-18.0.566/htoa-5.4.0_r1db094a_houdini-18.0.566/scripts/bin"

HOUDINI_PATH = "C:/htoa/htoa-5.4.0_r1db094a_houdini-18.0.566/htoa-5.4.0_r1db094a_houdini-18.0.566;&"


Windows 10 and Houdini 18.0.566



Message 4 of 8
in reply to: Anonymous

same problem, I can render the same stuff no issues in OBJ level, and I can also render the same stuff with karma in LOPs but Arnold in LOPs specifically gives me this error

[HdArnold] Cannot load _htoa_pygeo library required for volume rendering in Solaris

here is my Houdini.env

# Houdini Environment Settings
# The contents of this file are read into the environment
# at startup.  They will override any existing entries in
# the environment.
# The syntax is one entry per line as follows:
#    VAR = VALUE
# Values may be quoted
#    VAR = "VALUE"
# Values may be empty
#    VAR = 

# Example:

PATH = "$PATH;C:\Users\masra\htoa\htoa-\htoa-\scripts\bin"
HOUDINI_PATH = "C:\Users\masra\htoa\htoa-\htoa-;&"

PATH = "C:/ProgramData/Redshift/bin;$PATH"
HOUDINI_PATH = "$HOUDINI_PATH;C:/ProgramData/Redshift/Plugins/Houdini/18.5.462;&"

OCIO ="C:\Program Files\Nuke12.2v2\plugins\OCIOConfigs\configs\aces_1.1\config.ocio"

Message 5 of 8
in reply to: Anonymous

Several people have already posted their environments, and cross-referencing them with the documentation they seem to be set up correctly. Was there some other part of the environment you needed to see?

My studio is also experiencing this issue and we have a pretty solid Houdini setup so I rather doubt that this is an environment issue. Any other ideas?

Message 6 of 8
in reply to: Anonymous

tis broken. you can get vdb with volume node into solaris arnold will render it but with default density, any volume assign won;t work. if try render volume from sop it just ignore it and drop this warning.

and yes the envr is correct !

Message 7 of 8
in reply to: Anonymous

update to my comment, I managed to make it work but importing the vdb sequence with a "file" LOP node instead of "SOP create" or "SOP Import" nodes

Message 8 of 8
in reply to: Anonymous

Hello, this problem is still happening in 2022.
plz fix
[HdArnold] Cannot load _htoa_pygeo library required for volume rendering in Solaris

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