When I try to generate ISOGEN in AutoPlant SS4, SS3 Refresh and SS3 from model that was created in AutoPlant SS1or SS2 olets are dimensioned from the outside of pipe rather than from the centerline of pipe.
This is happening because of the COP_OLET Component Preference is not set for older drawings. The COP_OLET Component Preference allows to change olet “length” dimensioning process. From center of pipe when enabled or from outer diameter of pipe. Isogen for most cases just supports Center Of Pipe. However, in some particular cases and angular olet configurations, there is need to have Outer Diameter of pipe as reference. This component preference was implemented starting from AutoPlant SS3
Paste following line to AutoCAD command line, this will set COP_OLET variable to 1
(at_pipingsystem_setvariable "COP_OLET" "1" )