Dwarf Fortress Bug Tracker - Dwarf Fortress
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0003371Dwarf FortressPathfindingpublic2010-10-04 23:182015-03-26 12:36
0003371: Non-fliers end up on top of walls (swapped positions with flying pets etc?)
I've had several non fliers end up on top of walls that have no access. Both dwarves and tame animals. They rarely have business up there (I've had some kittens kill vermin on top of walls, but there were way too many kittens for the number of vermin there.
Build some walls with exposed top and no access and wait for creatures to end up on top.
I have some mods, but nothing deep. Several new reactions, new workshops, [PET_EXOTIC] -> [PET], some civ changes, etc.
creature swap
has duplicate 0004218resolved Footkerchief Creatures getting stuck on top of inaccessible/unreachable walls 
has duplicate 0004381resolved Footkerchief Dwarves somehow end up on unreachable walls, unable to get down. 
related to 0006452resolved Footkerchief Save crashes unless military is disbanded 
related to 0008253new  Dwarf removing construction gets "creature swapped" onto construction tile, removes floor beneath his feet 
related to 0009061new  Sharing squares with animals makes dwarves climb trees 
Issue History
2010-10-04 23:18jaxad0127New Issue
2010-10-05 03:41Logical2uNote Added: 0013204
2012-03-19 07:13FootkerchiefRelationship addedhas duplicate 0004218
2012-03-19 07:13FootkerchiefRelationship addedhas duplicate 0004381
2012-03-19 07:14FootkerchiefNote Added: 0021599
2012-05-03 16:51XelsolNote Added: 0022426
2012-05-03 16:52XelsolIssue Monitored: Xelsol
2012-05-04 06:07ellindseyNote Added: 0022428
2012-05-07 15:29hyndisNote Added: 0022448
2012-06-23 13:30QuietustNote Added: 0023096
2012-06-23 16:06FootkerchiefNote Added: 0023098
2012-06-23 16:50DrazinonondaNote Added: 0023099
2012-06-23 22:09FootkerchiefSummaryNon fliers end up on top of walls => Non-fliers end up on top of walls (swapped positions with flying pets etc?)
2012-07-12 20:18musicmastermshNote Added: 0023216
2014-03-04 18:32FootkerchiefRelationship addedrelated to 0006452
2014-09-07 01:01FootkerchiefRelationship addedrelated to 0008253
2015-03-26 12:36LociTag Attached: creature swap
2015-09-02 10:45lethosorRelationship addedrelated to 0009061

2010-10-05 03:41   
1. Critters just can't randomly gain the flier tag, so are you sure there's no access?
2. And even if you could guarantee there was no access, it seems like you've made a lot of changes, so there's also a possibility there's some cascading error. You'd have to demonstrate this happening on a non-modded game.
2012-03-19 07:14   
Orkel uploaded screenshots at 0004381:
http://horobox.co.uk/u/Orkel_1301379878.png [^]
http://horobox.co.uk/u/Orkel_1301448385.png [^]
2012-05-03 16:51   
Just happened to me (0.34.07). Two dwarves ended up on a wall that surrounds the entrance to my fort. There's no way up there (or back down, save dodging off of it) and there's nothing around it for them to climb on and dodge off onto the wall. The only thing I can guess is a kobold or goblin thief made it close enough to the entrance to scare someone chilling outside and forced them to dodge up onto the wall.

In my last fort, I had a waterfall and dwarves would regularly "swim" up to an inaccessible area (think salmondwarf), but there was no real problem because they always found their way back down (forced down by the water).

The mods I use are Mayday's tileset and NoExotics.
2012-05-04 06:07   
I have seen this happen several times in my current 34.07 fortress. The dwarf who it keeps happening to has multiple flying pets (trained giant sparrows). In my case it seems to be associated to the dwarf trying to retrieve an animal needing training so he can take it to a training animal. If the animal is up on a wall, the trainer somehow ends up on the wall too.
2012-05-07 15:29   
I've seen this as well in 34.07. It always happens without me noticing and its only be sheer chance that I notice this before the dwarf dies. The dwarf cannot fly, there is no combat, no bridges, no falling onto the object from above, no ramps, and yet somehow the dwarf gets up onto the ledge.

I have no idea what is causing this, but it seems to be rare. Cannot reproduce this at all. Seems purely random.

As a workaround for this I ensure I have ramps or stairs to every roof, so just in case Urist gets himself onto the top of a 5 story building somehow, he can get down without starving to death before I notice.
2012-06-23 13:30   
I suspect that what may be happening is that a flier on top of the wall decided to move down into a dwarf's tile and they swapped positions, leaving the dwarf stranded on top of the wall.
2012-06-23 16:06   
Can you elaborate? Does DF actually swap creature positions to resolve pathing conflicts?
2012-06-23 16:50   
It does on occasion. The easiest time to see it is in a workshop, when one dwarf comes to collect something from the shop (e.g. recently-made crafts) while a dwarf is working in the shop. Sometimes, though not always, the dwarf stepping into the shop will displace the one working, though I don't think that interrupts the work. You do see a brief position swap though.
2012-07-12 20:18   
I've lost two dwarves to this in the last week. Nothing above the walls, many many ravens and owls flying all over the place. I had no idea how they were getting up there until I read the above just now. It's getting really annoying.