Open sp map.(Im using metropolis as an ex.)
Open gemini.
Check parse and recursive in metropolis(sp map).
After you checked both boxes go to the bsp tag and click the sbsp/blah/blah/efwe4g
Then click save and save it anywhere you want.
Once your done saving go back to gemini and click build at the bottom right.
Then you click the .info file of the bsp you just extracted.
Once youve clicked build and w/e you just now converted the bsp. Congrats.
Written by meh.