Stress Isometric does not create a drawing file, why? Reason #6.
The following appears when trying to create a Stress Isometric:
Is not a recognized file format
Notice that all files but DGN file are created:
Reset Profile Preference using procedure here.
Afterwards, open model and try to create a Stress Isometric.
Reasons why stress Isometric was blank or does not create a drawing file?
OPIM Stress Isometric Troubleshooting Guide