Some insights on Zombie ai.

[Zourin]

I took some time to run some defense tests. I wanted to see what could make an effective defensive setup given the new AI. Obviously, the need to learn the new quirks is essential to survival. To not do so can only get you overwhelmed, particularly in SP.

 

The test subjects were a fairly basic 25 stack of Arlenes. Tests were conducted in daylight, but I feel it fair to assume the additional bulk will offset Horde variety and speed.

 

Design:

First, I created a killbox 9 blocks long and 3 blocks wide, filled the bottom with wood spikes, and lined the side with wood spikes. The walls were made of cobblestone 'brick' (upgraded flagstone). This left an 1x2x8 direct path designed to whittle down or kill zombies single file.At the defensive side, I put 1/4 SCTR's to create a 'sturdy' firing lane.

 

Second, to encourage pathing, midway on either side of the 'killbox', I built a 2-3 high wall extending 15 blocks in either direction.

 

 

First Results: All Arlenes took a 15+ block detour to go around

Adjustment: Boxed in firing position.

Second Result: Same results. Arlenes did NOT go for the direct spike path.

 

Suspected cause: Zombies will NOT path through spikes if ANY alternate path is available.

 

Design adjustment

Walls were converted to 'tower defense' hallways 1 wide and 3 tall, following the path the Arlenes took.

The right-hand side hallway was fitted with two sets of double-doors set face-to-face with them at the entry and exit points.

The left-hand hallway was fitted with a floor of wooden spikes.

 

Third Results: Arlenes pathed completely around the outer perimeter to the left, ignoring the option to use the doors, and ignoring the spike path.

 

Conclusions (so far)

 

- Spike pathways appear 'last resort' for zombie pathing. Zombies will not willingly walk on spikes if there is any alternate route within the vicinity.

 

- Doors are not 'invisible' to AI pathing as initially suspected. Single doors are merely structural weakpoints, like screen doors on submarines. Put enough door HP in the way, and the AI will detour.

 

Other notes:

- Spike traps and a bow are insufficient damage to ward off 25 arlenes without needing retreat options. It is fair to assume it will be wholly inadequate to directly confront feral hordes given their gang bonuses to block damage once they reach the 1/4 blocks.

- Barbed wire does essentially no damage, approximately 1hp every 2-3 seconds. This occurs only if you 'touch' the wire.

- Barbed wire provides approximately 2 seconds of snare per block a zombie has to move through. Using a 2-wide 'barbed wire hallway' creates an interesting 'slow field', but does insufficient damage to assist kills with low dps weapons before they hit the 1/4 boundary.

- Barbed wire takes damage each time it deals damage.