How do I fix a door not opening correctly?

[Krakatoa Magma]

Something that's bugged me for years is having doors that do not open correctly. I'll set it to the usual open then close, and sometimes, but rarely, I'll get a problem where the door does animate, but it does not open. What's the reason behind this, and how do I fix it? This is something I usually just avoid and delete, but this time I wanna figure it out and keep it considering the level is almost nearly complete. I've attached both a 3D view and the wireframe so you can see the problem a bit better. I almost want to doubt that the problem is because the room below is in another sector, but if that's the issue then lemme hear it.

[Nevander]

Looks like that surrounding wall isn't void space and is instead an actual sector that is either lowered to the floor or raised to the ceiling. Hover over it and press delete to make that sector into void space, retexture it and test your door.

[Krakatoa Magma]

1 minute ago, Nevander said:

Looks like that surrounding wall isn't void space and is instead an actual sector that is either lowered to the floor or raised to the ceiling. Hover over it and press delete to make that sector into void space, retexture it and test your door.

ah. so it was that easy of a fix. Thanks for this, honestly after all this time I didn't even realize that was the problem.

[Nevander]

Yea for reference, doors in Doom by default will open to 4 units below the lowest adjacent ceiling, so the ceiling or floor here is made in such a way that the door breaks and fails to open. You might could also make the door free standing by drawing a very thin V-shaped sector at the two sides of the door, so you end up with something like this:

 

|>=====<|

 

Where the separators are the sides, the signs are the new sectors and the equals are the door. That would pull the door sector itself away from the adjacent geometry and allow the door to open without deleting the other sector.