Continuing the discussion from Torus as Fillet:
In the case below, not only does V9’s _FilletSrf create a surface of revolution (per RH-75374), with the Trim option enabled, the input faces are also trimmed correctly. I don’t know which YouTrack issue, if any, pertains to this fix.
FilletSrf_Simpler_and_correct_trim_in_V9.3dm (89.5 KB)