Answer:
Yes,
If OPIM is not installed the following will appear when trying to use the feature:
---------------------------Bentley AutoPIPE---------------------------Unable to generate Stress Isometric. Please install OpenPlant Isometrics Manager.---------------------------OK---------------------------
Note:
1. In order to use the Stress Isometric feature with an AutoPIPE Advanced or Nuclear edition license currently enabled, OPIM needs to be downloaded and installed separately from AutoPIPE. OPIM can be installed before or after AutoPIPE, it does not matter. OPIM only needs to be installed if planning to create a Stress Isometrics. Otherwise OPIM does not need to be installed.
2. Version of OPIM must match version mentioned in AutoPIPE's readme file / release notes (ex. for AutoPIPE 12.06.00.048, only install OPIM 10.09.00.074).
Never update OPIM unless a new version of AutoPIPE was installed and again reference AutoPIPE's readme file to confirm version of OPIM to be used.