Cataclysm-dda: Overrun scenario having trouble spawning

[curstwist]

Describe the bug

Military base scenario, overrun, is having trouble spawning on default settings map.

Steps To Reproduce

1. create a debug world
2. try the scenario start, overrun.

Expected behavior

it spawns easily.

Screenshots

Versions and configuration

win10, vanilla world.

[RarkGrames]

I have now the same thing on generation. Most of the generated worlds can't spawn the location. I removed the unique flag, added occurrence: [ 0, 1 ], and that made it work ten out of ten times. I never worked with the unique flag, so I have no idea what can be tweaked to make it spawn properly.

[curstwist]

Cool, glad you found a setting that works for fields.

[ralreegorganon]

I removed the unique flag, added occurrence: [ 0, 1 ], and that made it work ten out of ten times. I never worked with the unique flag, so I have no idea what can be tweaked to make it spawn properly.

Basically because the unique flag makes the occurrence a % chance to spawn the given special as a mandatory special, the current configuration for the special was making it so that it had a 10% chance per overmap of being spawned. Once it's rolled a success there, it's still got to meet all of the other criteria in order to actually place (e.g. appropriate terrain, distance from city, etc).

When the game starts and tries to place you in a location, it'll generate overmaps out to a radius of 3 from your starting overmap when trying to find the location, and so for each overmap it'd be doing this roll (10% chance) and then trying to find a valid placement.

About the only thing you could tweak about the unique flag would be to increase the chances that it picks it to spawn at all.

[RarkGrames]

So basically this means that as long as it uses the unique flag, there will be failed generation cases. I guess this makes it a no-go for this location.

[ralreegorganon]

Even without the unique flag, you're gonna have some failed generation cases.

For example, with the update here that makes it occurrences: [0, 1] and strikes the unique flag, that just means it'll spawn between 0 and 1 times per each overmap. When the game goes to place the specials, it first gets all of the mandatory (min occurrences > 0), tries to place all of those, and then gets a random selection of the optional (min occurrences == 0) and tries to place them.

There's no guarantee it'll place it then either, and the odds go down the more specials there are in the pool to pull from and the more restrictive the constraints on the special.

Worth noting that the unique flag is still just on a per overmap basis rather than global, so even if it was working, you could still (through rng) run into the location on every single overmap.

[RarkGrames]

Thanks for the clarification. Then it seems a more overarching solution is needed for cases like these (rare locations needing guaranteed spawns).