What's with these weird lines in prBoom?

[everennui]

They are about 1-2 x 1-2px wide and extend from sectors that usually have a door or sectors that have a top and lower elevation.

I guess I've seen these on linedefs within a sector as well (lighting sectors).

I can typically get rid of them by putting a sector in front of them usually 2x2px box.

[Linguica]

Slime trails? http://doomwiki.org/wiki/Slime_trail

[scifista42]

They might also be unclosed sectors, which would be worse, because while slime trails are purely visual errors, unclosed sectors also affect game physics and potentially break other parts of your map if you continue editing it. Unclosed sectors come to existence when you delete linedefs between different sectors, which you should never do unless you join/merge the sectors first. You can discover unclosed sectors via Map Analysis Mode (aka Error Checker) in (GZ)Doom Builder, and fix them by redrawing the affected sectors (or just clicking them while in Make Sectors Mode, which usually works too).

But as you describe them, they're probably slime trails.

[everennui]

Linguica said:

Slime trails? http://doomwiki.org/wiki/Slime_trail

Winner winner, chicken dinner.

[everennui]

Is this the only way to get rid of them?

[baja blast rd.]

Shifting vertices around often helps. They generally happen when you have lots of irregular geometry, so vertices in those areas should be jiggled with.

[Ribbiks]

what version of prb+ are you using?

I noticed some time ago (after that fancy wiggle-fix update?) that software graphics got soo much nicer. maps that used to be littered with slime trails (erm... including nearly everything I've made) were down to a spurious few. that update is pretty much the reason I play in software now.

But yeah, unfortunately the fix seems to be move some vertices around and roll the nodebuilding dice in hopes it will play nicely

[Gez]

Using ZDoom nodes (which allow fractional vertex precision) allows to remove or at least greatly reduce slime trails; though it'll reduce a bit the number of source ports that can load your level.

(Not that much, though, since besides the obvious they're also supported by PrBoom+, Eternity, and Crispy; and then some ports such as Doomsday always build their own nodes anyway.)

[kuchitsu]

Also some nodebuilders might be better at this than other. This might be worth experimenting with if it's a constant problem for you.