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Rendering with Arnold in Houdini and Solaris using the HtoA plug-in.
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Cannot add nodes in Arnold Vop

Message 1 of 12
1237 Views, 11 Replies

Cannot add nodes in Arnold Vop


I am having trouble adding nodes in the VOP networks in Houdini 16.5 (Indie) with Arnold 5

When I enter the Arnold_Vop net I see no option to add nodes. Similarly, while I can add an Arnold Standard Shader node in SHOP, once I enter it, again I cannot see any way to add nodes.


The only two options available are

- Null

- Subnetwork


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Message 2 of 12

This is an installation problem. probably your HOUDINI_PATH is not set up correctly yo include the HtoA install directory. Did you install Redshift? Can you show your houdini.env file contents?

Message 3 of 12
in reply to: singhs_apps

I don't have Redshift.

Houdini env file contents :

# # 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: # # HOUDINI_NO_SPLASH = 1

# htoa config start HOUDINI_PATH = "/Users/mukeshsingh/htoa/htoa-2.2.2_ra19eea7_houdini-16.5.323/htoa-2.2.2_ra19eea7_houdini-${HOUDINI_VERSION};&" # htoa config end

RMANTREE = /Applications/Pixar/RenderManProServer-21.6

PATH = /Applications/Pixar/RenderManProServer-21.6/bin:$PATH


Message 4 of 12
in reply to: singhs_apps

your path should be like this:

# htoa config start
HOUDINI_PATH = "/Users/mukeshsingh/htoa/htoa-2.2.2_ra19eea7_houdini-16.5.323/htoa-2.2.2_ra19eea7_houdini-${HOUDINI_VERSION};&"
# htoa config end

Message 5 of 12
in reply to: singhs_apps

It is as you have posted.

Copying the env file contents into the editor formats it.


Message 6 of 12
in reply to: singhs_apps

You have only HOUDINI_PATH variable, where is the PATH variable?
reinstall or replace your env file with this one:

PATH = "$PATH;/Users/mukeshsingh/htoa/htoa-2.2.2_ra19eea7_houdini-16.5.323/htoa-2.2.2_ra19eea7_houdini-${HOUDINI_VERSION}/scripts/bin"
HOUDINI_PATH = "/Users/mukeshsingh/htoa/htoa-2.2.2_ra19eea7_houdini-16.5.323/htoa-2.2.2_ra19eea7_houdini-${HOUDINI_VERSION};&"

Message 7 of 12
in reply to: singhs_apps

I am not sure I follow you. The env variable was automatically set when I Installed Arnold. Adding the extra line as per your suggestion above returns the same error as my original post.

Message 8 of 12

Can you double check that that HOUDINI_PATH line starts with a new line? It looks like it starts with a comment in the text that you posted.

Message 9 of 12
in reply to: singhs_apps

The Houdini Path is on a single line :


I removed the htoa folder and reinstalled Arnold. The error persists.

@rachid Hadj Abderrahmane

The second line you suggested isn't required on macOS.

Reiterating my issue :

I can launch the Arnold render node. I can even Render using Arnold.

I just can't create any nodes inside of Arnold Standard shader or Arnold Vop Network.

Message 10 of 12
in reply to: singhs_apps

Arnold Standard is deprecated, so forget about using that. Standard Surface is the shader to use.

Can you start Houdini from a Houdini terminal? Then you should get an HtoA startup log. If you don't, then increase the log verbosity and get an Arnold log for a test render. And get the Show Details from Help > About Houdini.

// Stephen Blair
// Arnold Renderer Support
Message 11 of 12
in reply to: singhs_apps

It seems the online Document is sparse and out of date. Arnold v5 has a slightly convoluted way to build shaders inside of Houdini.

Step 01: Build a test geometry, add Camera and Arnold light in the OBJ context

Step 02: Enter SHOp context, build Arnold Vop Node. Dive inside

Step 03: create "subnetwork"node, dive inside and create your shader network.

Message 12 of 12
in reply to: singhs_apps

@Stephen Blair

How do I start Houdini from a terminal on mac os?

I can create shaders, render etc via Arnold.

It's just that unlike the tutorials and online documents of Arnold to Houdini, The Arnold vopnet shows only two options - option to add a null node and a subnet node. I can dive inside the subnet and create shaders, but that's diving one extra level deep just to create shaders when I am already inside an Arnold vopnet.

Is that an expected behaviour ?

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