Q&A: Wall Breaker AI and how it works

[nonameclan]

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Possible bugs above



Does anyone know why WBs continue to widen the gap at the first layer walls? Happen to me 4-5 times now.

As you can see, I usually bring around 10-12 wallbreakers with me and I deployed two of them per set. The first set dig the hole on the first layer but then the 2nd set and 3rd set go to left and right and widen the gap on the first wall layer. There is no comparment there to attract the following sets. The 4th set still widen the gap even more and finally Finally, I can get to the second layer with my 5th set.

Well, does it mean now we have force to take all building at the first layer in order to reach the second one (even if there is no nearer compartment)? That's plain stupid. No problem for a base but imagine there are lv7 mortars and xbows (lv1-3) behind the second layer wall. Those things will kill your troops if you dont reach second layer fast enough and spend time clearing the buildings behind first layers.


Sincerely, I hate new WB. I have to use them more than ever before and they also take 2 spaces now. Doesnt mean that I didnt try to learn and use them. I understand the concept and basic of their AI now but the problem above still happen. (Which according to their AI, they shouldn't do that)

Also, with new AI we have to destroy any nearer single useless compartment before we can go for the 2nd layer or even worse the 3rd layer. That's almost impossible to reach the deep side of the base with really strong defense (LV 70-80+) before your troops were killed.


New WB AI does a lot better against some types of bases but do worse against another certain types of bases. The increasing splash radious is great for offense, bad for defense but I generally think the AI of WB is worse and it take 2 space camps now.

[lubenthrust]

I don't have a definitive answer, but I can speculate. Two possibilities:

1.) You took out the buildings next to the blown gap in the town hall compartment before releasing your additional wallbreakers. In this case, the wallbreakers might have started drawing diagonal lines to the other buildings in that compartment. Timing could have been unlucky; you cleared the first compartment with archers, blew the gap, archers poured in hole and killed the buildings in the town hall compartment next to that hole. Then you launched your second set of wallbreakers and they targeted diagonally.

2.) We've been told that wallbreakers look for the closest enclosed building. To determine which building is closest, the game is obviously computing the distance (either 2-norm Euclidean or maybe 1-norm Manhattan, http://en.wikipedia.org/wiki/Lp_space) between the launch point and the building itself. Perhaps walls in the way contribute a small penalty to the distance. So, for example, if two compartments were exactly 5 spaces away from the wallbreaker, but one compartment had a single wall while the other had a double, it would go for the single wall. If this was the case, perhaps the penalty was big enough to cause the wallbreaker to head to one of the cannon compartments due to the double thickness wall.

Regardless, I try not to send wallbreakers against the center of a long wall anymore. Too many opportunities for something like this to happen. If I breach a wall with my 1-2 wallbreakers, but see 3-4 widen the gap, I immediately stop and try to blow up at least one surrounding compartment (or take out its occupant) before trying wallbreakers at my initial position. That seems to break the tendency to widen gaps.

Also, why did you black out your gem total? Nothing to be ashamed of.

[lubenthrust]

Diagram credits to vanzabee.

I personally destroy all of the first layer before moving on, but I see their point.

I wouldn't even bother waiting to destroy the first layer. Instead, I'd use 2 wallbreakers to blow either the left or right T-junction, then try my original attack down the middle again. It seems to reset the pathing logic when you do so.

[Junliang]

I wouldn't even bother waiting to destroy the first layer. Instead, I'd use 2 wallbreakers to blow either the left or right T-junction, then try my original attack down the middle again. It seems to reset the pathing logic when you do so.

Huh.

1) that was an overly simplified diagram.
imagine that as only 20% of a th9 base.
lol.

2)your method is inefficient in terms of wb usage.

[lubenthrust]

Inefficient, yes. Any waste is bad.

...

But it is a lot more efficient than throwing wallbreaker after wallbreaker at a gap when all they do is widen it further. If wallbreakers 3-4 widen the gap, I don't put 5-6, 7-8 in the same place. I blow a compartment to force a change in the pathing logic, then try again.

"Insanity is repeating the same mistakes and expecting different results."

[Zombiebender]

Does anyone know why WBs continue to widen the gap at the first layer walls? Happen to me 4-5 times now.

I think the issue here is with how wall breakers, and any troop really, decide to run through a gap to get there target or open a wall. If buildings in the corners aren't destroyed and enough walls are surrounding them it will still see them as protected. If it targets them it will try to destroy the wall that it thinks are protecting them. If you were to deploy a WB near the right corner it will blow that wall for the same reason.

[21delta]

This is exactly what Maggie was describing to me, happened to me 2 times, the wbs just went to widen the hole... Strange behavior indeed.

This is in fact, part of the new ai behaviour. If you had cleared all the buildings in that first compartiment, then the wb would go throu the hole to the next compartiment.

[nycwaiting]

This is in fact, part of the new ai behaviour. If you had cleared all the buildings in that first compartiment, then the wb would go throu the hole to the next compartiment.

The new wb AI seriously sucks. I have to rethink my layout as well as attack strategies again. Frustrating that we can't break the inner layer as we used to before.

[Hannibal]

I don't have a definitive answer, but I can speculate. Two possibilities:

1.) You took out the buildings next to the blown gap in the town hall compartment before releasing your additional wallbreakers. In this case, the wallbreakers might have started drawing diagonal lines to the other buildings in that compartment. Timing could have been unlucky; you cleared the first compartment with archers, blew the gap, archers poured in hole and killed the buildings in the town hall compartment next to that hole. Then you launched your second set of wallbreakers and they targeted diagonally.

2.) We've been told that wallbreakers look for the closest enclosed building. To determine which building is closest, the game is obviously computing the distance (either 2-norm Euclidean or maybe 1-norm Manhattan, http://en.wikipedia.org/wiki/Lp_space) between the launch point and the building itself. Perhaps walls in the way contribute a small penalty to the distance. So, for example, if two compartments were exactly 5 spaces away from the wallbreaker, but one compartment had a single wall while the other had a double, it would go for the single wall. If this was the case, perhaps the penalty was big enough to cause the wallbreaker to head to one of the cannon compartments due to the double thickness wall.

Regardless, I try not to send wallbreakers against the center of a long wall anymore. Too many opportunities for something like this to happen. If I breach a wall with my 1-2 wallbreakers, but see 3-4 widen the gap, I immediately stop and try to blow up at least one surrounding compartment (or take out its occupant) before trying wallbreakers at my initial position. That seems to break the tendency to widen gaps.

Also, why did you black out your gem total? Nothing to be ashamed of.

Not sure I like either explanation. The AI seems able to path along diagonals in other situations without impacting on nearby walls. What's different here? Also, in examples like this, when the hole widening stops, the wb doesn't go off on the diagonal you'd expect if that was the reason for impacting on the wall. They finally continue forward and break the next wall. Regarding #2, I've been collecting examples of hole widening like this and there's no shortage of them with single walls exclusively.

I'm personally the fence as to if it's impacting on the wall because (1) it thinks it's freeing a building or (2) it cannot identify a building to free. I have separate hypotheses that might support either behavior, but I'm struggling to explain all the examples of hole widening I've collected with a single theory.

Given how often the examples occur when the wallbreakers are launched essentially right on the wall and without any buffer of distance, I even considered for a while if it might be a simple deployment bug. But I've since had examples of remote deployment that led to hole widening.

All the examples I've collected to date were central on a long compartment. So I agree with your strategy for dealing with it. A corner deployment might be another good way to avoid this behavior.

[motionsickness]

im also wondering why theyd go for the double walled enclosure instead of a single one with the cannons in it.