Romero tweets that Doom is 3D.

[Maes]

But is Doom a raycaster....?

[Phobus]

A 3D game with a limited z-axis is still a 3D game, I'd agree, but the 2.5D shorthand is helpful to distinguish it from games that don't have "infinite height" actors and can actually draw a room under/over another room. I don't think the use of sprites makes a game 3D or not, as many fully 3D games used 2D sprites for decorations. Forza Motorsport 3 was one of the best-looking Xbox 360 games, certainly at the time of release, but the audience and a lot of the foliage were 2D sprites with billboarding.

[Redneckerz]

3 minutes ago, Phobus said:

A 3D game with a limited z-axis is still a 3D game, I'd agree, but the 2.5D shorthand is helpful to distinguish it from games that don't have "infinite height" actors and can actually draw a room under/over another room. I don't think the use of sprites makes a game 3D or not, as many fully 3D games used 2D sprites for decorations. Forza Motorsport 3 was one of the best-looking Xbox 360 games, certainly at the time of release, but the audience and a lot of the foliage were 2D sprites with billboarding.

That's pretty much how i viewed it. 2.5D does not mean anything in a technical sense, but its a good term to distinguish, i guess, certain rendering setups back in the day. It easily explains the technical difference between a Doom or a Quake, even if the term technically makes no sense at all.

 

Especially when Quake happened, the term was in use en-masse (I still have some mags around from the time that refer to it ) to basically describe any title that didn't do every aspect in 3D space like Quake did.

[Maes]

A better way to think of Doom as a 2.5D game is to compare it to a full flight simulator or the closest FPS to one, Descent. There you don't only have a fully 3D world, but also meaningful control over the third dimension. In Doom you can only go as high (or low) as the floor you're on allows, though the flight and "freelook" capability in Heretic surely must add something towards that "2.5D".

 

Unlike a pure 2D game, there is occasionally an interaction with a third dimension (e.g. you cannot jump off a cliff if there's a too low ceiling right in front of it). Even if you could say that even that interaction would be reducible to a door/impassible line in a 2D top-down game, it is still dimension-dependent (on Doomguy's height/width). Still, nothing that couldn't be done cleverly in an ostensibly "pure" top-down 2D game a-la Alien Assault. But then you have to decide if you really want "pure" 2D or 3D games ;-)

Edited June 17, 2020 by Maes

[Bauul]

I was curious what E1M1 might look like if it was actually just a 2D game.  Not too great it turns out!

 

 

[Doomkid]

5 hours ago, TheMightyHeracross said:

"2.5 D" isn't a real thing. You can't have "half" of a dimension.

In a literal sense this is completely undeniable, but most people are using the term 2.5D as a colloquialism. It may as well be synonymous with "very limited 3D" or "3D engines that rely heavily on sprite-based graphics".

 

Of course, from a mathematic/geometric perspective, "half a dimension" is total gibberish, not something that can actually exist.. but the term is "easy" so people toss it around. (I say "easy" in quotes because everyone has to explain what they mean as soon as they say it, which makes it decidedly NOT easy..)

[RonnieJamesDiner]

30 minutes ago, Bauul said:

I was curious what E1M1 might look like if it was actually just a 2D game.  Not too great it turns out!

 

I must say, it certainly looks like it flows better without all of those pesky doors and annoying stairs.

[SaladBadger]

There are some fundamental bits of game logic where 2D is a bit of an afterthought, like projectile firing, where the projectile is aimed as if it was a 2D game, and then enough vertical speed is added to make it so the projectile will get to the right Z position when it gets to the right XY position (in practice, as Ling has demonstrated before, the distance calculation is inaccurate so in certain cases the z position is aimed wrongly), but this doesn't really mean anything. You can implement this kind of logic in Quake or Descent or even modern engines like Unity or UE4 as easily as you could in Doom. You wouldn't, of course, since this causes problems if an object has low XY distance but extreme Z distance.

 

 

[Chip]

of course this is my 420th post. 

[seed]

43 minutes ago, Doomkid said:

In a literal sense this is completely undeniable, but most people are using the term 2.5D as a colloquialism. It may as well be synonymous with "very limited 3D" or "3D engines that rely heavily on sprite-based graphics".

 

Or simply limited perspective. Platformers and fighting games like MK, SF, Tekken and so on are also fully 3D, but the perspective is only 2D, hence why they've also been referred to as 2.5D too.

[Revenant100]

10 hours ago, printz said:

I think the right person to ask about idtech1's dimensionality is @John Carmack, not just @Romero.

Carmack has answered this question several times over the years.

 

Romero has also answered this question before years ago.

 

Edited June 11, 2020 by Revenant100

[arnaldocsf]

25 minutes ago, LiT_gam3r said:

of course this is my 420th post. 

 

Well... 

Registered: 04-20 

[HorrorMovieRei]

Damn, what are we supposed to split hairs over now?

[Ichor]

15 minutes ago, HorrorMovieGuy said:

Damn, what are we supposed to split hairs over now?

 

Revenants: pants or no pants?

[arnaldocsf]

13 minutes ago, HorrorMovieGuy said:

Damn, what are we supposed to split hairs over now?

 

What is the correct form: DOOM, Doom or DooM? 

[arnaldocsf]

1 minute ago, Ichor said:

 

Revenants: pants or no pants?

 

Pants, obviously. 

 

It's a demon in his workplace.  

[MadGuy]

You know, I see many saying the Doom is 2.5D, but I thought that 2.5D is 2D games with 3D graphics not the opposite 3D games with 2D graphics (in terms of objects, enemies etc)

[Chip]

39 minutes ago, HorrorMovieGuy said:

Damn, what are we supposed to split hairs over now?

 

24 minutes ago, arnaldocsf said:

What is the correct form: DOOM, Doom or DooM? 

if memes on doomworld should be spelled MemE or MEME.

[Maes]

49 minutes ago, HorrorMovieGuy said:

Damn, what are we supposed to split hairs over now?

 

Why, doomguy's haircut, of course.

[intacowetrust]

Anything that gives the illusion of perspective is '3D' to me - that's the key as far as I'm concerned. Doom, Wolf3D, even games like Hired Guns on the Amiga or Road Rash on the Megadrive/Genesis.

 

The difference between all those titles and an engine like Quake however is that they restrict themselves to a subset of 3D, or particular special cases that render quickly or where certain tricks can be used.

 

With Doom it's the lack of view pitching and Wolf3D of course lacks height variation and flat texturing, which makes it easier to use pre-computed column scaling routines. Hired Guns restricts view points and angles to a very small subset (which can be hand drawn), and Road Rash cuts out all rotations.

[Jayextee]

3 minutes ago, intacowetrust said:

Road Rash on the Megadrive/Genesis.

 

Road Rash has height-calculations; you can totally launch from the crest of a bump in the road and go over other traffic or hazards. You can even bounce off the top of cars if you're lucky with the timing.

It's 3D.

[Dark Pulse]

8 hours ago, TheMightyHeracross said:

"2.5 D" isn't a real thing. You can't have "half" of a dimension.

Hammerspace would disagree with you.

[JBerg]

2.5D's term is misleading. With idtech1, you're just dealing with a subset of what's possible in 3D space

[Quasar]

Carmack's discussion of the issue in terms of degrees of freedom is much more informative and well-defined than any debate over dimension number ever will be. Any view that uses a perspective projection is essentially implementing a 3D game. That includes stuff as primitive as Wolf3D or Hovertank 3D. The calculations done to project walls are a subset of the generic matrix transform that is used to turn any 3D viewpoint into a 2D displayable image. But talking about the degrees of freedom available gives you a lot more information about what the particular engine is capable of.

 

Doom and its "alikes" cannot roll the view because they render walls as vertical strips of constant z-depth, and only implement a single simplified case of affine scaling for horizontal ceilings and floors. They can likewise only pretend to pitch the view by using vertical frustum shifting for the same reasons. Put a differently coded renderer onto the same game engine with the same data though, and suddenly those things are possible just fine. Even while explosions and monster scratches still remain "2D" in nature simply because they fail to consider the Z axis even though it exists.

[Gregory Stephens]

How can I still call Doom one of my waifus if it's 3D and not 2D? :( 3D is gross!

[taufan99]

13 minutes ago, Lynnie said:

How can I still call Doom one of my waifus if it's 3D and not 2D? :( 3D is gross!

If it still can't touch me IRL, it's 3D in theory and view only. :((

[DoomGater]

Doom is 2D. Otherwise it could not be played on a FLATscreen. right??

[Graf Zahl]

On 6/12/2020 at 8:07 AM, Quasar said:

Carmack's discussion of the issue in terms of degrees of freedom is much more informative and well-defined than any debate over dimension number ever will be. Any view that uses a perspective projection is essentially implementing a 3D game. That includes stuff as primitive as Wolf3D or Hovertank 3D.

 

Let's put it this way: Wolfenstein is a 2D game with a 3D renderer. I think that mostly fits the facts.

 

[FractalBeast]

On 6/11/2020 at 6:02 PM, Bauul said:

I was curious what E1M1 might look like if it was actually just a 2D game.  Not too great it turns out!

 

Spoiler

 

 

Excuse me, that's just a video of Corridor 7!

Edited June 14, 2020 by FractalBeast

[DSC]

On 6/11/2020 at 7:32 AM, ReaperAA said:

Our savior @Doomkid already resolved this issue years ago.

 

 

I immediately thought of that video upon reading this thread. Fun fact: I actually watched this video once a long, long time ago, before I joined the community, without knowing anything about Doomkid at the time. Man, who would have thought I would encounter and even speak to him long after that...