I recently made a map in the Twilight tileset and did not realize until I was 1/2 of the way done with the map and tried to save that this tileset can be played in Brood War only.
Is there any way to change this to a different tileset or convert it to a .scm without starting over?
Thanks
SCM Draft can change the tileset of a map. (or at least the version 1 could)
Although the conversion may not be pretty.
PS. Why does it matter?
Nothing current can do this well. Your best choice now is to redo the map. Scmdraft2 has an option now that doesnt work which would fix this. Which I think means that Suicidal Insanity hopes to do this in the future. Scmdraft 1 does a crappy job but it works. Maybe he doesn't have broodwar and is using Starforge or Scmdraft.
Is there a downside to playing it on Broodwar only? I like Twilight, it's pretty ><
Only if your playing Melee and you don't like the Broodwar units. Or at least thats my veiw on it.
Export all triggers and units. Then import them to the new map.
About terrain you're gonna have to re-do it since there are no good converting programs out there but here is a tip:
Open both maps in different windows and have the new one over the old one. Then you "trace" the old map unto the new one. As you move the map in the old map you move it in the new one and keep "tracing" the maps so you have the overall terrain concept of your other terrain.
Okay thanks guys.
Guess I'll have to start over

It was a melee map...so basically all there was was terrain.
To answer your questions...I own Brood War, but I am primarily a melee map player and do not like Brood War as much as the original...and my clan also plays the original...not Brood War. So I was hoping my map would be playable in all versions.
Thanks for your time all