Dear Oleg
In 3D, there are no stories, so there’s no way to determine a Current Story. In the past, this Global worked in the 3D script, but it was unreliable (since there’s no clear definition for Current story in 3D), so We’ve decided to make this unavailable in the 3D script.
To avoid compatibility issues though, we haven’t removed it completely yet, so now it returns a well defined value: the Home Story.
You can find this information on the following webpage as well:
http://gdl.graphisoft.com/gdl-docs/gdl-guide/chapter-12-miscellaneous/request-options/
“…Should be used on floorpan only, as “current story” is not defined in other view types…"
Best, Kata