Exporting .OBJ

Hello everyone, I'm an italian Cacoman so my english isn't very good but i hope you can understand me. I need to export a map in .OBJ file format and i see there is this kind of opportunity in the export menu, but when i try to do this no file is saved. Do you know how to solve this problem?

Do you mean Doom3?

If so, then in the level editor, you choose Selection -> Export -> to .obj

Choose a location to save your .obj file. It should save the .obj file to that location.

I'm using Doom Builder in Doom 2 "mode". If you go to Export... and check file extensions you'll find the .obj file format but, if you click "Save", it doesn't save anything.