The OpenDSS changes the default path when you open a file in a DSS window. Therefore, you do not always have to set the path in the Compile command or in a separate Set Datapath= --- option.

The present data path is always displayed in the window header. If you change to another path, you can get back to the first by rightclicking in a window for a file from the desired path and selecting "Change to this Directory" from the popup window.

You may still use Compile command or the Set Datapath option to set the default datapath if you find that more readable.