Flat "Bleeding"

[scwiba]

I've been mapping for a while now, and every once in a while I get this effect I can only refer to as a flat "bleed" when testing maps. I've seen it only a couple of times in other WADs, but I can't recall any names.

What occurs is basically a flat "bleeding" into another sector where it isn't supposed to show up. The effect can only be seen when standing in specific locations. I often think it happens where a lot of vertices are lined up, but other times that doesn't seem to be the case. If I move things around a little, the issue will often go away.

Does anyone know what I'm talking about, and if you do, how to prevent it from happening? I don't know how to explain any better. I'd post a screenshot, but I don't have anywhere to host it.

[CodeImp]

Sounds like you are talking about "slime trails". Are these small vertical lines stretching from the sector's edges to the top or bottom of your screen? These are inaccuracies of the nodebuilder and the Doom engine, some sourceports have workarounds coded in to reduce this anomaly. Other than trying a different nodebuilder or changeing your map to make it less complex, there isn't much you can do.

[Ezxariarch]

there is no real way to get rid of ALL the bleeding. Since BSP, the amount of flat bleeding has been greatly reduced. You will always get tiny ones (about 1 pixel wide) in just the most random of places. But if your flat bleeding is REALLY beg, like the entire floor is bleeding, then you need a better node builder.

[Epyo]

Jesus, 7 threads down this question is asked :(

[Neil]

Epyo said:

Jesus, 7 threads down this question is asked :(

Yes, but with a most unhelpful subject line. That's not really RoneKyakone's fault.

[EarthQuake]

Usually you get slime trails with linedefs going at odd angles (like having lines with a 'slope' of 1 over 400), so a good way of getting rid of them is moving vertices where the problem occurs. Typically you can trace their position by finding one and heading in its direction, although you have to move in the exact direction or else you may lose it.
Sometimes they are really bad though and bleed through half of the level. Heh, I've had cases where they were so bad, I could see other parts of my level on the automap.

[Vegeta]

The way you describe and name this is fascinating, yet a screenshot would be great. Use the the "check for bugs" option that many editor have, if you are more for the manual work, move the vertices may be there's a problem there, use the "sector mode" and check if all the sectors are closed, run a good bsp (idbsp and zennode are particulary good), if the problem persist you can either upload the wad in a public server (not the archives) and let other to check it out, or the drastical but efective solution, remove the sectors that cause problems and redo the structure (this sometimes is better as you tend to make it better than before and the time it requires may not be too long, yet tedious).

[Macro11_1]

Hey Rone, If your talking about what Im thinking your talking about, then its easy.

Ok If Im wrong, dont kill me :P

Anyways, Try making a new map, with 2 sectors joined by one line def.

Then raising the floor of one, then go test it in some port and stand on the lower floor.

That is what I know as to be flat bleeding, where a line with a upper or lower section showing with out a texture and so the engine compinsates for this by drawing the ceiling plane over top of it.

To fix said problem in that example map, just put a lower texture on that 2 sided line definition.

IF THIS IS NOT THE CASE then I dont know what your talking about and am sorry for wasting your time with this silly post. :P

[scwiba]

Epyo said:

Jesus, 7 threads down this question is asked :(

My bad. I apologize for that.

Alas, Macro, my problem isn't as simple as just missing textures. I guess I didn't explain it as well as I could have. I'm fairly certain it's slime trails that I'm running into, judging by what everyone has said.

Nothing came up on an error check on the map, but I was finally able to get rid of the slime trail by moving a few vertices.

At the moment, I'm using the nodebuilder that's built into DoomBuilder. I see ZenNode mentioned here and in the other thread, so next time I have this problem I'll look into it.

Thanks for the help.

[EarthQuake]

Currently, error checkers cannot check for slime trails. I might be wrong on this, but I believe they are caused by the imprecision of rounding decimal values. Like I said, if you have a linedef in your level with a slope that the engine does not like, then slime trails can result and the best way to fix it is to move vertices of that linedef to readjust the slope.

In my experience, changing nodebuilders rarely helps.

And just for clarification, when I use the term "slope", I'm talking about how many units a line "rises" for how many units that line "runs" on the X/Y coordinate system. For example a 30 degree angle will rise one unit for each two units across it runs.

[EarthQuake]

Vegeta said:

The way you describe and name this is fascinating, yet a screenshot would be great. Use the the "check for bugs" option that many editor have, if you are more for the manual work, move the vertices may be there's a problem there, use the "sector mode" and check if all the sectors are closed, run a good bsp (idbsp and zennode are particulary good), if the problem persist you can either upload the wad in a public server (not the archives) and let other to check it out, or the drastical but efective solution, remove the sectors that cause problems and redo the structure (this sometimes is better as you tend to make it better than before and the time it requires may not be too long, yet tedious).

Here's one on e1m1, courtesy of the Doom wiki:
http://doom.wikia.com/images/9/9b/E1m1_slime_trail.png

[Enjay]

EarthQuake said:

Here's one on map01...

Looks more like E1M1 to me ;)

Yeah, I remember spotting that years ago. It's amusing that this persistent bug was visible on the very first Doom map that many people played.

[EarthQuake]

That's what I said ;)

Enjay said:

It's amusing that this persistent bug was visible on the very first Doom map that many people played.

That's perhaps where it got it's name.

[Csonicgo]

EarthQuake said:

I've had cases where they were so bad, I could see other parts of my level on the automap.

This is actually a common problem. many many levels suffer from this, even legendary megawads. Still, I really question why the 1024 compilation has so many of these trails.