For some reason, it's never really made sense to me that sliding/swinging polyobjects have to use the same sound closing that they use opening. When you have a futuristic sliding door in a tech level that resembles a regular Doom-style door, having the door opening sound play when it's closing (such as it was done in ZDCMP1) doesn't seem right to me.
The ability to define a sound both for when a polyobject moves from its "resting point," if you will, and for when it moves back to that point (assuming the possibility that it may not be used as a technical door), would come in handy. I realize that with ACS using Thing/SectorSound (seeing as they are point sounds) you can work around this, but if you end up getting several seperate polyobjects that use this idea, the number of scripts it would take would just end up becoming nothing more than clutter.
PolyObjects use open/close sounds
Moderator: GZDoom Developers
This has already been done for post-2.0.98. See how door sequences are defined in the latest SNDSEQ.