Merry Christmas!
No idea if this is what you had in mind but it seems to work fine.
The map is attached in my last post.
Edit 2: Attached a third map, fixed a bug where I was referencing _Index instead of _Loop. Thanks ILH.
Edit 3: Attached a 4th map. I forgot to clean up a memory leak :O
Notes:
- I didn't bother replicating the transparent fade in effect on the falling presents because that would've been a pain to do in GUI, but I think it's fine without it. Maybe the author can incorporate that into the actual model animation.
- The "CONFIGURE ABILITY FIELDS" section in the Start Cast trigger is where you can really customize the settings. Keep in mind that you can break it if you choose weird values. Try to stick with whole numbers when possible and remember that the Loop trigger runs on a 0.02 second periodic interval. Also, the Follow Through Time on the actual ability is meant to match the value used in the SAir_Duration variable (1.00 by default).
- It wouldn't be difficult to remove the channeling aspect from the ability. Delete the Stop Cast trigger, set the Follow Through Time on the Channel ability to 0.00, and adjust the Start Cast trigger to use A Unit Starts The Effect Of An Ability event instead of the channeling one.