Weird collision with walls in large maps

[El Inferno]

I just discovered for myself that if I try to make something in a map (boom format) at distances about 20000 from the origin then something goes wrong with collisions with walls. Is there a way to deal with this issue? Maybe something to do with nodebuilder? And what is the "safe" zone to avoid these kind of things in maps? 

Also I heard that the height cannot be too large, what is the limit?

[Mordeth]

You can determine if your (block) map size is too large with (any) GZDoombuilder editor by pressing F4, selecting 'map size' and running the check. Doom has a map size limit of 64k, so about 22300 x 22300 units.

 

Note that this doesn't compute actual level area, but the distances between the extreme polar coordinates of your in-editor geometry. Four small square sectors should fit well within the limit, but place those four squares 23k map units apart and you'll break the blockmap.

[El Inferno]

On the doomwiki it's written that it is possible to compress the blockmap if there are a lot of blocks with no linedefs inside. Is there a tool for that or how it can be done?

 

Say, I have a giant 20000*10000 sector with nothing inside and want to have some structures on both sides of it.   

[tourniquet]

ZokumBSP is able to compress blockmaps and or exclude tagged parts of the map from the blockmap itself.

[El Inferno]

Hm, I found some solution for the blockmap problem by looking at the sunder maps. 

It seems that if I delete the blockmap from the wad (using slade) and replace it with an empty lump then the issue with collision dissapears. I guess the source port manages to generate the blockmap more efficiently than UDB. 

 

I'm still not quite sure why this problem appears in the first place, though. Here are the lump sizes for my map:

 

Nothing seems too large here but still I experience some troubles with blockmap apparently...

[zokum]

A vanilla compatible blockmap can only cover map sizes up to a certain size. It looks like your map spanned a larger area than that. From the game engine's view, there is no area outside the blockmap that you can have linedef collissions with. I don't know which exact blockmap format you used, most likely a "larger" one than the vanilla one.

I would guess you ran into problems with an unsigned blockmap, the limit of that one is about 128kib + overhang.

 

Edited January 9, 2021 by zokum

[El Inferno]

5 hours ago, zokum said:

I would guess you ran into problems with an unsigned blockmap, the limit of that one is about 128kib + overhang.

 

Perhaps. Does the format of the blockmap depend on the nodebuilder I'm using? I haven't seen any mentioning of the blockmap in UDB settings.

 

Btw, I switched to ZDBSP and it seems that the blockmap problem gone (at least for now).

 

 

Thanks everyone for the answers!

[zokum]

5 hours ago, El Inferno said:

 

Perhaps. Does the format of the blockmap depend on the nodebuilder I'm using? I haven't seen any mentioning of the blockmap in UDB settings.

 

Btw, I switched to ZDBSP and it seems that the blockmap problem gone (at least for now).

 

 

Thanks everyone for the answers!

There's really only two formats of blockmap. The vanilla one and the unsigned one that some ports support. The more hitech ports do not need the blockmap.

ZokumBSP will one day feature 32bit blockmap (the current format is 16bit).