[2022] Help understanding zombie AI

Originally posted by SuperMeatBag: …they are I think programmed to try and avoid taking damage if possible.

Originally posted by aY227: …They know spikes will hurt them…

I still don’t think this is true. It seems more plausible that there wasn’t enough space left to go that way in the zombies’ view.

When the zombies ‘see’ a spike field, they don’t see a bunch of sharp pointy sticks. They see a block. An obstacle. So to see it from their perspective, imagine placing a regular old block everywhere you placed a spike. Now the situation may become clearer.

I’m still guessing since we didn’t see the base exactly, but my hypothesis is that the spikes were placed such that there wasn’t enough head room above the spikes and below the ceiling at some point along what you intended to be a path. So the zombies ‘thought’, I can’t go that way or I’d hit my head. Therefore it’s not a valid path without breaking blocks. Therefore that path gets lumped with other paths that require breaking blocks. And if all paths require breaking blocks, they go into area destroy mode.

I’ve had multiple builds that thwarted the zombies where I wasn’t trying to, simply because something grazed or would graze their heads in a way I never even considered would be a problem for them.

Originally posted by aY227: If there is no other way they will walk through it, so how they can see it as a block? It's not a forcefield block. Also they don't attack spikes.
Traps have just bigger AI pathing penalty.
Still doesn't explain why they decided to switch to area attack instead of go through. I think there was seriously A LOT of those traps - so penalty was so massive that AI decided it will be better to level building.

Its like that for years.

The spikes have this property:

And the documentation says this:
(A17) The Path property This is a shortcut for the AI pathfinding and quickly determines that this block (like a forge or pillar100) can not be pathed into from any direction. Blocks using Model cube, cube_glass and cube_frame are automatically flagged.
So whatever else may be true (I didn't say it was a forcefield), they treat spikes as if they were full blocks. Which could mean they didn't think there was enough room.