Using as previewer

If you need a previewer, you can use raindrop as one and integrate it with your BMS editor. The following steps are for iBMSC, but should apply for BMSE too.

First step

The working directory of raindrop when ran through iBMSC is going to be where iBMSC is, so you need to copy your config.ini and GameData folder to where you have iBMSC.

Second Step

Go to Options -> Player Options. Click "Add" and set Path to wherever your raindrop exe file is.

For each box, put in the following:
Play from beginning

-p -i "<filename>" -A

Play from current measure

-p -i "<filename>" -m <measure> -A

Stop

-S

And you're set - now you can use raindrop as your previewer.