Anyone know of a mod or trick to control the way doors open? For example I need a door which is placed on the bottom right corner of a room, to open inwards (inside the room) - hence with the handle on the left (not the right). This is actually standard behavior - you typically want the door to swing towards the wall perpendicular to the door when closed. Advance apologies if this is a long-solved issue, but I searched this forum and Google and couldn't find much on it, except someone mentioning using the arrow keys to control the way doors swing - but I couldn't figure out how that works. Thanks in advance!
This is (probably) correct, of course, above me. Could swear this stuff was on the Wiki.
It used to be it was by the outer-side would face us, as we Placed it (if there was enough room between us and where we were trying to Place it, with it not-Placing it backwards, otherwise). Also there's the issue of whether it's the nearer-or-further edge of a Block from us, we're aiming at (if that even makes a difference).
And the Aiming Angle. This has become especially-obvious, Placing Barrels, lately (with 1.14).
So which-side of 45º (looking either that-way upwards or that-way downwards) seems to make a difference. When in doubt, test-with Stairs (but notice that the Barrel Will have a given singular-side, one can use as a Ref. Pt. for-Sure).
To answer the modded question, there is the Malisis Doors mod (dedicated entirely to custom types of door objects, including an actual custom door you can build in a machine and give specific properties to). This mod doesn't let you change how the door object works, but it does let you change how it's opened, how long it stays open, what sound (if any) it makes when you open it, what the door is made out of, whether it's a double-door or not, and whether it has a lock of some sort. I don't recall there being any other mods that focus exclusively on doors, but there are plenty of mods that include customizable doors as part of their larger featureset:
Quark (I think) changes how doors open such that double doors always open together (but otherwise work/look/sound as they do in vanilla).
Little Tiles has the ability to create functionally-customizable doors, such that the literal way the "door" opens doesn't actually look or act like a normal door (for example, you would use this door object to create a desk drawer that you can actually open or close or piano keys that press down when you click on it [actually playing a sound would require the use of redstone machinery and specifically command blocks]). The range of effect for the door is something like 16 blocks, so you can have a fairly large area to create a custom movement map. This mod specifically allows the creation of highly-detailed custom blocks and highly-detailed custom multiblock structures (given the proper amount of hardware capability, these can be around the size of your entire render distance).