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: Keep in mind, in order to use the Stress Isometric feature in the Advanced or Nuclear versions, OPIM needs to be downloaded and installed. OPIM can be installed before or after AutoPIPE, it does not matter. OPIM only needs to be installed if planing to create a Stress Isometrics. Otherwise OPIM does not need to be installed.