[Minecraft] Is pathfinding strange? Summary of reasons why villagers and mobs do not move as expected and countermeasures

If you are a villager:

• Go back to bed
• Go to the occupation block
• Flee from danger

For mobs:

• Follow the player
• Avoid obstacles
• Avoid falling

.

Recently common pathfinding problems/symptoms

① Villagers do not use bridges or stairs

Symptoms

• Do not cross bridges that are clearly passable
• Stop in front of the stairs
• Choose a circuitous or meaningless route

Reasons

• Villager AI only recognizes “safe and reliable blocks” as passages
• If it includes fences, trapdoors, carpets, etc.
  It will be determined that there is a possibility that it cannot be passed

② Villagers do not recognize occupation blocks

Symptoms

• No occupation assigned
• Wandering around instead of going to work
• Exchange contents are not updated

Reasons

• In pathfinding,
  The route to the occupation block is determined to be “unreachable”
• Routes are often cut off due to doors, steps, and ceiling heights

③ At night, villagers are in heavy traffic jam

Symptoms

• Villagers gather in one place at night
• Unable to go to bed and panics

Reasons

• Route search to bed runs at the same time,
  AI processing causes conflict/clog
• Beds are too crowded

④ Mobs lose track of the player or fall

Symptoms

• Zombies and enemy mobs suddenly stop moving
• Falling directly from a height

Reasons

• If height differences, half blocks, or water flow are involved
  Path search may fail midway
• Especially likely to occur in Bedrock version

Differences between Java version and Bedrock version (important)

👉 “Simple path” is especially important for the integrated version (Switch/Smartphone)

Measures and improvements you can take right now

✔ Passages are based on “full block + 1 block width”

• Avoid half blocks
• Reduce carpet/pressure plates

✔ Unify steps with “stair blocks”

• Stable design with no jumping

✔ Ceiling must be at least 2.5 blocks high

• Villagers will not pass if there is a “possibility of hitting your head”

✔ Bed and occupation blocks are arranged in a straight line

• Reduce turns and branches

✔ Reset villagers once

• Put it on the boat and unload it
• Take it outside the chunk and bring it back

There are many cases where behavior can be improved just by doing this.

Criteria for determining “Is it a bug or a feature?”

• It moves the same every time → There is a high possibility that it is by specification
• Fixed by restart → Temporary AI glitch
• There is something wrong with a specific version → Possibility of a known bug

Recently in Minecraft,
“As the AI has become smarter, overly cautious behavior” has been increasing.