How To Make An Invisible Bridge In an Doom WAD?

Hey guys, I need help on how to make an invisible bridge if I ever feel like making one in one of my Doom WADs. If you don't know what I'm talking about, then here's an example of an invisible bridge:



This is from MAP03: Aztec of The Plutonia Experiment, and as you can tell, I'm standing on the invisible bridge. I used the cheat codes idclev## to warp to the level, idclip to get to the area quiclkly, iddqd so that the monsters don't kill me & idfa to get all weapons and full ammo (which I used to kill off the monsters with the BFG9000 in the room with the invisible bridge).

So can you guys help me out please?

What port do you intend on doing your map for? The method and/or difficulty will vary depending on that.

I believe what you need to do is surround your bridge with another sector that is at the same height as the surrounding water/nukage/lava.

Have the actual bridge at the height you want it at.
Select the bridge sector and remember the number of the sector. (For example: Sector 1)

Then select all the linedefs that make up your bridge's sector

Let's say that your bridge sector is number 1, and the sector around it is number 2. The linedefs that make up your bridge sector will have a reference number of 1 on the side facing the bridge sector and 2 on the side facing the surrounding sector.

Change the reference numbers for the front or back sides of the linedefs so that they are both 1, or more accurately the same as the bridge sector's number.

And that should make it work.

A super-easy and non-glitchy way would be to insert a bridge thing
if you use zdoom or Skulltag.

Krispy said:

A super-easy and non-glitchy way would be to insert a bridge thing
if you use zdoom or Skulltag.

All fine for ZDoom stuff, but if you want monsters to cross it, it ain't gonna happen.

NitroactiveStudios said:

This is from MAP03: Aztec of The Plutonia Experiment, and as you can tell, I'm standing on the invisible bridge. I used the cheat codes idclev## to warp to the level, idclip to get to the area quiclkly, iddqd so that the monsters don't kill me & idfa to get all weapons and full ammo (which I used to kill off the monsters with the BFG9000 in the room with the invisible bridge).

So can you guys help me out please?

Haha - you know you can start Doom on any level using the "-warp ##" command line parameter right? Likewise, entering "-nomonsters" on your command line when starting Doom and warping to a level will remove all of the monsters. If you're using a launcher warping to a map is almost gauranteed to be a drop-down menu too, which is even easier.

To answer your question, open the map in Doom Builder (or whatever your editor of choice is) and have a look! It's a simple trick which I managed to pick up by studying the example in MAP02 of Plutonia. An explanation of what is being done would be that you basically have two sectors set up, one inside the other. The outer one lends the appearance to the whole effect and is set up normally and level with the surrounding sector. The inner one is used to set how high the "bridge" will be and what size and shape it is - the only thing special about it as that the front sidedefs and the back sidedefs of this inner sector BOTH reference the same sector ID (note that this isn't the tag). This method works in all source ports and the original engine, as far as I'm aware. I just did a check in ZDoom and that works without having the outer sector (as in, you just have the normal sector for your water and the bridge one that has both sets of sidedefs referencing it's sector ID) - I'm fairly sure this isn't safe for vanilla though.

This is called a self-referencing sector.

I took some of the advice to help me with the invisible bridge, and I got it to work! Thanks guys!

Phobus said:

Haha - you know you can start Doom on any level using the "-warp ##" command line parameter right? Likewise, entering "-nomonsters" on your command line when starting Doom and warping to a level will remove all of the monsters. If you're using a launcher warping to a map is almost gauranteed to be a drop-down menu too, which is even easier.

Yeah I know, but it's more fun to clear out the enemies in the room with a BFG9000 rather that using a command line.

I don't understand how typing, for example warp xx in command line parameters can be easier than idclev-ing ingame...

It's faster, as you don't need to get into the game and then type the code. Likewise, if you do make a typo, you can catch and correct it easier on the command line. When you're doing this stuff often, you remove as many unnecessary steps as you can.

Well if you want to visit several levels it'll be faster to idclev than to quit and restart.

Also many people do not generally use the command line anymore.

As I mentioned before, if you're using a launcher (like I do) you'll probably have a drop-down menu to select which map to start on, which is even quicker. Even then, they do tend to allow the option to add command line parameters. Also, thanks to todays editors, you can test the map you're building from the editor itself, rather than quitting and then running Doom like I remember doing back in DEU2. I'd agree that it is quicker to idclev## if you're looking around multiple levels for whatever reason though.

Guys, I don't mind having to use cheat codes to get around places and stuff.

Anyways, I tried to make deep water and I looked at MAP02 in TNT: Evilution to get help, and I succeeded! This means I didn't have to ask for help on how to make deep water using a self-referencing sector.

NitroactiveStudios said:

Anyways, I tried to make deep water and I looked at MAP02 in TNT: Evilution to get help, and I succeeded! This means I didn't have to ask for help on how to make deep water using a self-referencing sector.

Always good to see someone at least try and do something on their own b4 they ask for help.

Nice. And good luck with the mapping. :)

Krispy said:

A super-easy and non-glitchy way would be to insert a bridge thing
if you use zdoom or Skulltag.

I hate responses like this. It's like asking a camper why he's rubbing two sticks together to make a fire when he could just use a lighter instead.

Take a look at the vanilla Doom editing guide here at Doomworld. This will get you up to speed. Depending on your port of choice, you can mix & match these techniques using more modern editing features.