[VANILLA] How to make a new kind of 3D floor! (Projected flats? I dunno what to call it lol)

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(Example WAD): [DOWNLOAD]

 

Local copy: 3D_projected_example_1.wad.zip

 

Hey DooDes, I've finally nailed a new kind of Vanilla visual trick (I thought the fake reflective floor trick would also break Doomworld, but no)! Here's what it looks like:

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NOTE: Screenies captured in Zandronum, simply for higher resolution

 

View from above:



 

View from below:

 

 

So, you want to learn more about it? Read on!

 

What will this work with?

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This trick works by making use of the Doom flat flood-fill behaviour. If you've ever noclipped outside a Doom map and noticed that the floors and ceilings seem to stretch towards you no matter how far away you are, that's the kind of thing it makes use of.

 

This means that it should work with all software renderers.

However, it should also work with GZDoom, SkullTag and Zandronum's OpenGL renderers, as they seem to emulate this effect (with the only real difference being that sprites are cut off if the flat overlaps them). I'm not sure about other renderers, but I expect GLBoom's will not work.

 

 

How useful is it, exactly?

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Sadly, this is the biggest catch - its use is rather limited, as the magic is broken simply by viewing the trick from particular angles. Its best use is either for far-off scenery, or for inaccessible ledges, such as high-up cliffs or blocky structures (like buildings).

 

Okay, let's quit stalling and look at some limitations:

1) The effect is "emitted" from walls

What does this mean? Well, it means that the "3D" floor has to be kind of... sandwiched between walls. If viewed from behind the platform, or from a weird angle, the effect breaks. Okay, you know what...? I think this would be easier to illustrate with images:





Sadly, this also means that, if you were to get creative with self-referencing sectors and allow the player to stand on the fake 3D platform, the effect would break.

 

 

How do I make it, then??

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Okay! Right to it! First, the easier kind (This only creates the flat from the bottom - looking at it from above will produce a HOM) - here's what you should finish with:

 

View from below:



View from above:



 

STEP 1

First, make the structure. You can represent the 3D floor with a midtexture for now.



 

STEP 2

Now, let's project the lower flat! We'll draw a sector around the platform, and lower the ceiling to where we want to project the texture.

(I'm using ugly textures to make it easier to understand what's what)





 

STEP 3

Now, raise the floor of the sector projecting the flat to 1 unit below the ceiling. (If we were to raise it to the ceiling, the engine would cull the flat, and the effect would be broken. Also, I've used a height difference of 8 rather than 1 here, to make it easier to see)



 

Now, let's run the game and see what it looks like!

(NOT SHOWN: me applying textures the the lower sides of the projector sector - you can do this too, now)



Beautiful.

As you can see from that slip of blue at the top of the screen, the flat is bleeding correctly, but nothing is showing behind the platform, so the effect is currently pointless.

Let's fix that.

 

STEP 4

Now, you can create a new sector around the edge and lower it to the "floor" of your platform. This is just so that a wall displays behind it. If you're worried about fake contrast, you can make this wall fit seamlessly with the one behind it by making this sector in front of the projector sector (he-heyyy, that rhymes!).





Psammo! It works!

 

 

Give it a try and amaze yourself with the actually very limited endless possibilities!

 

 

The next step!

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Now, here's the part where you can make it project a flat onto the top of the platform, too. This is where the trick really shines, as it's done on the fly without any need for moving sectors/etc.

 

STEP 1

Okay, let's back up a bit ~ make this structure again.



Now, make these four sectors.



Note: I've colour-coded them just for you! This should make it easier to keep track of.

Here's a colour key:

RED: Back wall sector: Used only to make a wall behind the platform. This time, however, it takes care of the wall on the bottom instead.

BLUE: This sector will project the "floor" of the platform. As far as I know, you can swap this one with the white sector, but I can't be bothered to test it.

GREEN: You can think of this sector as a "filler" sector if you like - it's only there to make sure the engine renders the "bottom" of the platform.

WHITE: This sector will project the underneath of the platform, as in the easy method.

 

STEP 2

First, if you want a wall below the platform, raise the red sector's floor to where the ceiling of the platform would be.



Then lower the ceiling of the blue sector to 1 unit above where you want the floor of the platform, then raise the floor of this sector to where you want the floor of the platform. Texture the upper sides.



 

STEP 3

Leave the green sector as-is, then lower the ceiling of the white sector to the height you want the underside of the 3D platform to be, and BAM! You've only gone and done it!

Here's what you should have:

 

Have fun! I hope you crazy kids find tons of creative uses for this. :3

 

Bonus: Combine it with self-referencing sectors!

[axdoomer]

In Doom: The Mars Missions, there's a 3D platform and you can walk on it. You can also see under it, but it's not meant for the player to walk under it. 

 

I also saw a similar trick elsewhere and it could be used to do 3D windows through which you could see the sky. The window was over a corridor, but you could still walk there. 

[Doomkid]

Great tutorial, Kapanyo!

[AD_79]

Very cool. I've seen (and used) this type of effect before but never considered the possibility of having both the top and the bottom flats being visible, so thanks for this!

[Revae]

Super neat.  Always like seeing new vanilla tricks.  You nailed it.

[Guest Unregistered account]

  On 4/29/2017 at 11:11 PM, axdoomer said:

In Doom: The Mars Missions, there's a 3D platform and you can walk on it. You can also see under it, but it's not meant for the player to walk under it. 

 

I also saw a similar trick elsewhere and it could be used to do 3D windows through which you could see the sky. The window was over a corridor, but you could still walk there. 

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Oh, right! I haven't played the Mars Missions, but now I guess I'll have to c:

 

As for the second effect, I don't know if it's the same instance you're referring to, but Gothic DM uses a technique to achieve that effect. The difference is that it uses multiple midtextures to hide the gap on the ceiling.

I would link the example presented by Doomworld's editing pages, but since the Forum update it seems the page has been lost :c

[Graf Zahl]

Sadly you didn't include the map to check it out within the game, so I cannot tell which effect precisely this is. But since you say that GZDoom can handle it but GlBoom probably not, is this in any way related to how the bridge is done in the first level of BTSX E1?

 

[BigDickBzzrak]

And I thought my maps couldn't get much hackier than they already are. How wrong I was.

Thank you!

[Guest Unregistered account]

  On 4/30/2017 at 8:55 AM, Graf Zahl said:

Sadly you didn't include the map to check it out within the game, so I cannot tell which effect precisely this is. But since you say that GZDoom can handle it but GlBoom probably not, is this in any way related to how the bridge is done in the first level of BTSX E1?

 

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I'm not sure, but I'm fairly sure that takes a different approach, as this method produces the effect from walls, and the bridge in BTSX seems to be independent. An example WAD should be uploaded soon!

[Mordeth]

This editing trick is ancient. I'd like to link you to the old Doomworld Editing tutorials, except @Linguica seems to have broken it during the transition. It's called "fake 3D bridge" but is more commonly known as the "Mordeth bridge".

[Guest Unregistered account]

That is incorrect, because the Mordeth bridge works by not allowing you to view the top of the bridge while you're not on it. If you could, the flat would bleed towards you nonsensically.

 

This trick allows you to create platforms which display a flat on both the top and bottom without any visual errors (depending on how you implement it).

 

However, it makes sense that one would confuse the two, as they both revolve around using flats in weird ways.

Edited April 30, 2017 by Unregistered account

[esselfortium]

  On 4/30/2017 at 10:30 AM, Kapanyo said:

I'm not sure, but I'm fairly sure that takes a different approach, as this method produces the effect from walls, and the bridge in BTSX seems to be independent. An example WAD should be uploaded soon!

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It's not used for that bridge (which is instead a variant of the mordeth bridge technique), but this does seem similar to the effect used for the 3D overhangs in BTSX E1's final hub map's outdoor scene, and in E2's "Unbaited Vicar of Scorched Earth".

[Mordeth]

  On 4/30/2017 at 11:44 AM, Kapanyo said:

This trick allows you to create platforms which display a flat on both the top and bottom without any visual errors (depending on how you implement it).

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That's "merely" an extension of the same effect. For more fun (but relying on sidedef sector reference abuse instead), check the secret Quake-remake level of Requiem (the famous drop-down into a room below) or the ikspcial tutorial WAD on /idgames showcasing room-above-room corridors. Both by Iikka Keranen. Still, very nice to see people interested into doing tricks the vanilla way instead of immediately assuming gzdoom.

 

[Graf Zahl]

That Requiem map of course has its share of problems making the trick visible.

With hardware rendering it is a hopeless affair to emulate and in a software renderer that allows looking up and down it also quickly shows its limitations.

Not to mention that it totally whacks ZDoom's Trace function.

 

For its time it was cool but these days I guess most users will preceive it as a bug, not a feature, if they use a port that allows more than just looking straight ahead.

 

[esselfortium]

  On 4/30/2017 at 3:45 PM, Graf Zahl said:

That Requiem map of course has its share of problems making the trick visible.

With hardware rendering it is a hopeless affair to emulate and in a software renderer that allows looking up and down it also quickly shows its limitations.

Not to mention that it totally whacks ZDoom's Trace function.

 

For its time it was cool but these days I guess most users will preceive it as a bug, not a feature, if they use a port that allows more than just looking straight ahead.

 

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This is why the player is prevented from standing underneath them in BTSX. If you can only see the effect from outside the 3D sector, the effect is completely seamless. I'm pretty sure they also work in GZDoom's hardware renderer.

[Graf Zahl]

If you mean the BTSX stuff, yes, that one works fine. When I played the official release I didn't notice any problems, even the one that prompted me to add a compatibility setting for the earlier version was no longer present.

 

I was talking about the Requiem map in particular, which does not work at all in GZDoom (I have seen variations of this effect work in other maps, though) and glitches in ZDoom's software renderer when looking down.

 

 

[Mordeth]

  On 4/30/2017 at 3:45 PM, Graf Zahl said:

 if they use a port that allows more than just looking straight ahead.

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If people adapt vanilla tricks for Boom-compatible maps, things get interesting again with Boom's "property transfer" action (242). You no longer need to have physical raised floors or lowered ceilings... you can bleed from faked flats instead. In the case of Requiem / ikspcial, you can get rid of an awful lot of control sidedefs that way as well and end up using just the fake floor rectangle and the fake ceiling rectangle. That is much more robust, both in setup and visuals. You'd still end up using an invisible moving 'bridge' sector to allow stuff either to stand above or underneath it (or a simple 3DMidTex grid for those ports that have it).

 

It -kinda- holds up to (limited) mouselook, but it is very finicky to get things working just right. However, any sprites just bleed through the whole illusion, not to mention monster behaviour that simply doesn't care.

 

Used to have this for E2 for elevators that move 'between floors' aka portal layers, but once linked portals were finished there was no need for them anymore and they got replaced with proper portal movement stuff.

[Guest Unregistered account]

Holy crap, I wasn't aware of Requiem pulling crazy magical shmizzle like that. I need to open it up and see how it's done!

[Revae]

Sucker.  It's mine now!  This is a neat little thing, though.  It's cool that there is always more tricks to learn for doom.

[Guest Unregistered account]

Holy shmizzles, what's that mod? Or are you making it? Looks fantastic either way; thanks for trying out the effect!

[Revae]

  On 5/1/2017 at 8:05 AM, Kapanyo said:

Holy shmizzles, what's that mod? Or are you making it? Looks fantastic either way; thanks for trying out the effect!

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No, thank you. It's REKKR. A vanilla tc. 

Not finished yet.

[BigDickBzzrak]

Here's a small demo WAD, runs on E1M1. You've got pillars there so that you can idspispopd on them and see the effect from above.

I hope I've done everything properly. Once again a million thanks to Kapanyo, you're the master, dude.

That first, more limited effect took me ages to figure out because I can't read.

 

test25.zipFetching info...

Edited May 1, 2017 by bzzrak

[Guest Unregistered account]

  On 5/1/2017 at 4:03 PM, Revae said:

No, thank you. It's REKKR. A vanilla tc. 

Not finished yet.

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Ah, right! Thanks. I still look forward to your WAD!

 

  On 5/1/2017 at 4:18 PM, bzzrak said:

I hope I've done everything properly. Once again a million thanks to Kapanyo, you're the master, dude.

That first, more limited effect took me ages to figure out because I can't read.

 

test25.zipFetching info...

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Thank you! ^^

I actually expect it took you longer due to my incompetence at explaining things rather than any errors on your part. :<

Edited May 1, 2017 by Unregistered account

[AD_79]

 

Quickly testing out an idea. Provided you don't get near it, the effect can be used for free-standing structures.

[Revae]

  On 5/2/2017 at 1:21 AM, AD_79 said:

Quickly testing out an idea. Provided you don't get near it, the effect can be used for free-standing structures.

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I imagine that wouldn't work if it had a wall rendering above it, and not the sky?  Or am I missing something?

[AD_79]

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Something like this, Revae?

[Revae]

A witch!
Lemme see a map or a .wad file, please.  I'm going to abuse the shit out of this on at least one map.

[AD_79]

Here you go.

[Revae]

Ah alright.  I thought it was actually separated from the wall.  Still neat.  Still going to abuse it.  Thanks!

[Guest Unregistered account]

Holy crapsicles, that's awesome x.x

Great to see people having fun with it!