Discontinuous navmeshes

[Elliebot-Z]

Splitting a vanilla navmesh is verboten. Whether new navmeshes with islands also cause problems needs research.

[mrudat]

As far as I know, a new completely disconnected navmesh causes stuff like NPCs stuck on the roofs in Sanctuary, because they randomly pick to spawn on the navmesh on the roof, but since there's no way for them to find a path off the roof, they get stuck there until the player leaves and returns.

I believe that that's the only impact of a disconnected navmesh; ie. it breaks sandboxing and anything that needs to have an NPC go from point x to point y while the player is there, but only if they happen to spawn on the disconnected navmesh.

Apparently, the Right Way to merge two vanilla meshes is to:

• merge the two adjacent but disconnected navmeshes (this deletes one of them, which is forbidden)
• resurrect the deleted navmesh record, so anything that references it won't asplode; specifically the problem is attempting to override or refer to a deleted record; the same reason why you should undelete and disable REFRs.
• maybe relink all of the records that used to refer to the old navmesh; I think the CK does this for you.
• trim it down to just one triangle to reduce the space it consumes
• move it so far away from the playable area that NPCs won't randomly decide to spawn on it

You would need to identify navmesh islands that:

• are close enough (sandbox radius I guess?) to contiguous navmesh that an NPC could spawn there when the player arrives
• are possibly large enough for an NPC to spawn on? - how many NPCs can stand on a navmesh island the size of the head of a pin? =)
• don't have a connecting (path-able?) load-door (eg. the balcony where you meet Preston Garvey)
• are close enough to some scripted interaction or possible combat that an NPC stuck on the navmesh is a problem
• edit: have anything at all on/nearby that an NPC might choose to sandbox with, making it more likely to spawn there