AI pathfinding algorithm sometimes leads to traffic jams
The AI pathfinding logic sometimes causes "traffic jams" of multiple NPCs attempting to path through the same small area. I have noticed this behavior to a small degree in several locations, but the situation that prompted this report was more severe than most.
In the St. Olms Waist Works (lower level center) there are two stationary barter NPCs around a central raised whickwheat bed. Two wandering ordinators had attempted walk in opposite directions past one of the stationary shop keepers, but because there's only space for a single person to pass, they were walking continuously into each other. While I was watching this situation to see what would happen, another wandering NPC joined the pile up. Eventually one of the ordinators turned 180 degrees and walked away, allowing the other ordinator to follow him (after some jiggling), and the last wandering NPC was eventually able to pass as well.
So the good news is that the AI did sort the situation out after about 30-45 seconds. But it's not obvious that the pathfinding actually aided in the resolution in any way. In fact, I'm suspicious that the ordinator that suddenly turned had been stuck long enough that the shortest path to his correct waypoint was suddenly behind him. If that had not occurred, there was the potential for this traffic jam to grow until it included most of the wandering NPCs in the area.
This ticket is clearly related to [[#2229 (closed)]], but I opened a new ticket because I believe that it's an independent previously unreported issue. I do not know if the original Morrowind exhibited this behavior, but I read the recent forum discussion on path finding, and thought that the possibility of "traffic jams" should be added to the list of considerations when evaluating whether a "complete rewrite" is in order.
(RM-2812 from redmine: created on 2015-08-01 by Cory Cohen, , closed on 2017-09-13 by nobody, relates #2229 (closed))