RORDoom source port question

Is there a particular reason that the RORDoom source port is the only one besides EDGE that allows for overlapping sectors? Why isn't this a standard feature in GZDoom or other advanced ports that aren't EDGE? 

The BSP tree that underpins Doom rendering and line of sight calculations operates on the principle that each X,Y coordinate on the map corresponds to one and exactly one subsector of a given sector. I don't know what RORDoom did, but it suggests that it somehow screwed with how the BSP tree operates, which is a pretty substantial change to the engine.

Because different ways to obtain ROR have been invented in the meantime; and they are overall much more robust.

Consider that overlapping sectors require the editor to not merge them. Which is a major annoyance from the user-interface aspect; because 99% of mappers are going to want to merge them as they are used; and even in maps made for RORDoom, automatic merging would still be preferred in most cases anyway.

So do modern 3D floor features basically outdo anything RORDoom could accomplish?

I didn't know EDGE does support overlapping sectors. Any example maps?

Technically, depending on how robust RORDoom's implementation was (I never tried it), it might have been able to do non-euclidean geometry.
Picture one opening on the right and one on the left, both going to the same "map space", but in different sectors with different floor and ceiling heights... If it was able to do this kind of stuff, then you'd need portals to duplicate that. But generally, yes.

3D floors have a lot more potential, though, because they can be translucent and non-solid, so they can be used to create pools, fog, special light effects, and so on; that overlapping sectors would never allow in any way.

42 minutes ago, LogicDeLuxe said:

I didn't know EDGE does support overlapping sectors. Any example maps?

I don't know, that's what the Doom wiki implied.

I don't see anything here implying that?

https://doomwiki.org/wiki/EDGE

https://doomwiki.org/wiki/RORDoom

Quote

RORDoom was created by Julian Aubourg and was the first Doom source port to have room-over-room capabilities. Based on Boom, it was released in 2000 shortly before EDGE, which provided a similar feature. EDGE gained in popularity, and RORDoom's authors stopped their effort.

Confusing  wording. The "similar feature" is 3D floors.

Ah makes sense.