With Houdini the installation is pretty simple and standard for Arnold custom shaders. All we have to do is to set the ARNOLD_PLUGIN_PATH environment variable on both Windows or Linux to rtoa/bin path.
Before that however check you have the following Arnold core : >= 7.3.3.1
(tested with Houdini 19.5, 20 and 20.5).
In Windows 10/11 click the win button and start typing 'env' you should get an hint like 'Edit the system environment variables', clicking on that it will open 'System Properties' .. at the bottom you'll find the 'Environment Variables'. You can then add the ARNOLD_PLUGIN_PATH user variable (or system variable) pointing to the rtoa/bin folder.
On Linux (>glibc2.23) you can set it up from bash if then from the same bash you gonna start Houdini. Simply write :
export ARNOLD_PLUGIN_PATH=/home/rtoa/bin
This will be lost when system is rebooted. If you wanna it persistent instead follow this simple guide:
https://mkyong.com/linux/how-to-set-environment-variable-in-ubuntu/
If you have problems loading the rtoa lib just type this in a bash terminal : 'apt-get install build-essential'
We rely on GCC for rtoa compilation on Linux and with the above you just install main libs to support that.
You then also need to add an RTOA_ROOT to your OS environment variables and let it point to the the rtoa folder.
Process is the same as for adding ARNOLD_PLUGIN_PATH however it's not yourpathto/rtoa/bin but only yourpathto/rtoa.
Once setup the sys var we can fire up Houdini and check if rtoa has been loaded.
If you don't have the console enabled you can still use the Log Viewer panel, load a rombo demo scene then setup Arnold to have 'info' verbosity.
Once the rtoa library is loaded we can access rombo tools materials from within Houdini.
As usual for Arnold shader add an Arnold Shader Network from shop. Double click it to expand the node. Once there you'll find rombo materials under Tools or simply hit 'tab' and look for Rombo Tools entry or start typing 'rombo'.
For the rombo scenes to easily work simply set the File->SetProject to the path where you downloaded RtoHoudini scenes. Take care that to have a lighter package we removed the .tx files so at a first run generating them may take some little extra time. You'll find many dev scenes not on the contents pages.
Eventually, load a scene and start rendering 🙂
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