First check you have the following Arnold core : >= 7.2.1.0 (tested on 3dsMax 2022 and 2023). 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’ ..[…]