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I don't know much about editing and have been wondering about this recently. Doom's maximum map size is too small for many of the open-world projects I see people discussing here lately. Would it be possible to make the maximum map size seem larger by reducing the player camera height, hitbox, and speed (as well as those of any other sprites)? It seems simple enough but I don't know if I'm missing something fundamental about (Z)Doom that would complicate the idea.

You should be able to do that no problem but there will be a lot that will have to change, including the player's JumpZ and the corresponding gravity amount on the level. (A shrunken world would require less gravity, for example). Obviously, all monsters and other actors would also need to be shrunk, as well, with their speeds altered.

After that, it should be simple enough to shrink textures down, especially in UDMF format, so that they fit the new scale. Moving sector speeds (doors/platforms/polyobjects) may also need adjustment, too.

I've thought about it too. I think the major thing you'll lose out on is 'resolution' in things like hitboxes and step height.

True - obviously, shrinking a map by a factor of 8 units would probably result in a some collision and hitscan issues, especially if the intent is to create an open-world map, but shrinking it by a mere factor of 2 still opens up a ton of space and shouldn't create these issues to such an extent that they would be noticeable.

There's another thing that I haven't thought of, though, and it is how the BSP and blockmap code would handle this. Obviously, when you create a shrunken map, you would add a lot more detail than the ZDoom engine would normally handle, and in my experience (I have dealt with some troublesome linedef-abusing mappers before!) that inevitably leads to issues down the line. As long as you try to confine your detail to textures, voxels/models, etc, and try and do it with fewer linedefs, it should be ok, though, I think.

I've had entire sections of maps disappear because of slime trail bugs, and inevitably had to remove a lot of linedefs (and details/slopes that went with them) to fix them.

I've done this before (unfortunately link doesn't work anymore, but it's really just an ultra large terrain-generated map with the player shrunken down, the use range shortened, things like that)

Definitely do-able but it's more trouble than its worth TBH.

Thanks for the responses! I hadn't considered the need to change gravity. I may do some tests to see how much you can reduce the player before the "resolution" issues kodi mentioned become bothersome. Nash, could you reupload that Tamriel map? I'm curious to see it.

Sorry it has long since been deleted. :/ Didn't even think to save it because it was something I put together really quickly just to mess around with shrinking the player...

No problem! How do you handle the large open-world environments in your current project? Is it hub-based?

Yes, hub-based, like Strife, or Hexen 2... so in a way it's not really "open world" in the sense that you can't see the entire landscape... and you have to make use of lots of 1-sided lines because GZDoom will choke if you can see the entire level at once. So it's more of an illusion, really... you will never be able to achieve true open world because there's no concept of LODs in the engine, everything is just drawn full detail at any distance, ALL actors and sprites are also shown fully... a complete opposite of how proper open world engines work.

While it would be a monumental task (if it's even possible) it would certainly be nice to have such feature, mostly because of how simple it is to create content for ZDOOM.

Hm. Trying to think of ways to limit scripts, actors, etc. based on sight. I mean, that's still a shload of world simulation, but you could ease things up somewhat with LOS and distance checks on various things. For example, the monster-multiplier in Doomvengers doesn't spawn monsters unless you can see them or are close enough. Still leaves the level rendering itself as the big issue.

I hadn't thought about LOD. So, as is, to make a large open world that runs at playable speeds it is probably necessary to either block player site or minimize detail. Does ZDoom's fog help with this, or does the game keep "rendering" everything, just in the fog's color?

Renders everything in the fog's color. Only time when something isn't rendered is when it's in a hidden BSP block or behind you. (Queue Edward850 yelling at me for being half correct. )

Fog doesn't do anything haha, everything is still rendered even if you can't see them. It's not like the N64 games at all

I did something similar concerning LOD for 3d models on Blade of Agony, maybe this could help somebody here.

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