[GM] precise checking

Hey I'm trying to make a game sort of like DDR with game maker but I need a few ideas on how to check if the player gets a good, bad, miss, or perfect hit when the arrows pass over the readin spot. Does anyone know how I'd go about doing this?

I would make masks, like 3 or 4, making the best one (perfect, if you want the normal DDR styled notes), the smallest, and if you press (whatever button for this arrow when it is on here) show sprite (perfect), add (___ points).  I need to explain clearer, and learn code for what I think.  I could do it in D and D.

Thanks, that'll help...but can you use more than one mask on an object?

You can change which mask an object is using, but unless you use a parent, no. Why would you need to, maybe I can find another way?

I can't seem to get anything to work by using different masks. The timing and stuff just doesn't work with that...Thanks, your help is greatly appreciated!