Answer:
Depends on your contract and workflow.
If you have access to using AutoPIPE Advance or AutoPIPE Nuclear version and would like to create a Stress Isometric, than Yes, download and install "OpenPlant Isometric Manager" and any prerequisites required. Again, remember that OPIM is a separate download and needs to be installed separately from AutoPIPE.
If you only have access to using AutoPIPE Standard edition, than No, do not download "OpenPlant Isometric Manager"
See Also
How do I download, install, and license AutoPIPE?