First check you have the following Arnold core : >= 7.3.3.1
(tested on 3dsMax 2024 and 2025).
Then simply set the ARNOLD_PLUGIN_PATH environment variable to rtoa/bin path.
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.
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.
Here romboReflectFlakes with a MapToMaterial.
To properly load Rto3dsmax demo scenes add their texture paths to AssetTracking -> ConfigureProjectPaths.
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