Ballista, What am I doing wrong?

[fatguy1121]

Is there something I can do differently to tackle a group of about 2,000 olm men? My plan was to use the Ballista to ween the numbers coming down the shoot and let the traps finish off the rest.

However, In testing, the dwarfs that are manning the ballista see the Olm men and get locked into combat bum rushing the enemies at full speed, completely abandoning the ballista. Even if I lock the door somehow through pure magic the dwarfs manage to fly over the walls and enter the kill chamber. Is there something I can do differently?

https://imgur.com/zO8yA0S

[Den Bjornen]

If the olm men are entering from that far left entrance, it seems like that is far enough that the dwarves on ballistas can get some shots off before freaking out. Maybe try digging a trench for a few tiles in front of the ballistas and put an accessible entrance to the trap hall more to the left. The current setup makes the enemies walk right next to the fortification in front of a ballista, so brave(or stupid) dwarves will climb through to fight.

There is also some possible weirdness involving constructed vs. carved fortifications. Apparently, built fortifications don't provide a "floor" on the top, so more things can get through.

[fatguy1121]

After some pondering, I think I'm going make the chamber full double width nearly the entire length of the shooting gallery, and block them from getting close to the ballista by relocating the door to the death maze about mid-way down. Does anyone know what the actual aggro distance is? I've seen as far as 20 blocks on a diagonal but cant find any data of what a reasonable distance would be to keep them from getting too close and aggro-ing the ballista dorfs.

Additionally, after some reading, I may have better luck using Vertical Bars in place of fortifications? Gonna try that and see if it stops these goons from walking through.

[Fel]

I initially had a 10 blocks gap between the closest point the enemies could get to and the balistas but it wasn't enough so I doubled it and it seems to work much better.
The "gap" is just a piece of corridor barred on both sides by fortifications.

I would also advise making the "safe" side a bit larger and put a stockpile for your balista ammo (it's called "siege ammunition" or something like that).
It would let your legendary siege operators shoot each balista several times while the enemies are in the corridor.

In case your operators are not very skilled, make a few catapults throwing at a wall+hole right in front of them and make sure to give the custom work detail for it to the dwarves supposed to man the balistas later.
Anything under legendary means not shooting perfectly straight, it's mostly alright at high skill levels but at very low skill levels the cone of fire means that a lot of ammo will hit walls and be lost.

[AlP]

Originally posted by fatguy1121:

Is there something I can do differently?

Have you tried turning magma off and on again?

[harlequin_corps]

Originally posted by AlP:

Originally posted by fatguy1121:

Is there something I can do differently?

Have you tried turning magma off and on again?

heh.
You have to put the ballista quite a ways away. Use only masterpiece ballista parts and when you know you will have hostiles coming in, change status to the middle one so a dorf dorf's the ballista. Ballista don't have a minimum range like catapults but still anything within view range will cause civilians to freak out.

[fatguy1121]

Well guys, This is the outcome. I will keep moving the wall even further away from the ballista until they stop going ham. I've searched high and low for definitive visibility or aggro range with no results. trying 18 now, but will likely need to move it even further. Next thing I will try is turning the magma off then back on. Thanks for the insight. https://imgur.com/a/OaPkXxY

[Morkonan]

Originally posted by fatguy1121:

Is there something I can do differently to tackle a group of about 2,000 olm men? My plan was to use the Ballista to ween the numbers coming down the shoot and let the traps finish off the rest...

I've read that the "fix" to keep those manning the ballista from charging the enemy they are targeting is to not allow them a clear path to the enemy...

You "might" be able to place the ballistae with the front part resting on the second tile away from Fortifications as one issue is that dorfs further than two tiles from fortifications can't see targets beyond them. (I think they can still allow the ballista to fire, though.) In any case, Ballistae and catapults can fire through fortifications, so you could put those dorfs in a room with Fortifications and deny them a path to the enemy. (Much like Crossbowdorfs)

You could combine the ballista with some tactically placed drawbridges and then smush the enemies into paste while the ballista watched... if you wanted to include the ballista in the battleplan. :)

An impassable trench in front of the ballista, filled with lava, two-squares wide... ?

Note: There's a bug where things can jump (or dodge/jump) through fortifications if they're on the same level as the fortifications. I don't know that it's intentional, though, just that they'll "jump" through them and they probably shouldn't be able to at that level.

[fatguy1121]

Welp.... The claim that dwarfs cant see enemies if they are two blocks or more away from a fortification is not the case. This didnt work. FYI, at this point I'm just going to make a maze of traps. Sad that the Ballista are basically un-usable.
https://imgur.com/a/7ja3zbP

[harlequin_corps]

Originally posted by fatguy1121:

Sad that the Ballista are basically un-usable.
https://imgur.com/a/7ja3zbP

This is.. not true. Ballista and Catapults are usable. What is true is attempting to use them at close range with low Discipline dorfs is less than optimal.

So. Discipline is a skill which, as it is raised, lowers the overall possibility that a creature will run from a fight.

DF and your dorf's actually presents the clue that one of the unmet/met needs is developing a martial skill.

Discipline is also raised when faced with friendly remains and death.

Putting your dorfs into squads with even a tiny training cycle of 1 month a year will satisfy that need regardless of uniform.

As your dorfs mature the overall discipline available within a fortress makes ballista more usable than in the early years of a fortress.

There is, however, a downside to high discipline. Civilians with high discipline are more likely to charge into a fight at unexpected times resulting in pretty much automatic death.
Dorf children are unique in that they have random levels of discipline that will eventually develop into more normal discipline levels upon reaching adulthood.

Ballista, to be "most" usable, for a given value of both Most and usable, have a .. "standard" setup to be used in base defense.

1. craft ballista parts until 3 Masterpiece ballista parts are made.
-This gurantees the least possible deviation based on the dorf's Siege skill.
2. Setup Catapults for quantum rockpiles.
-This raises the general population siege skill as each rock added to the quantum rockpile adds to siege skill, which further reduces deviation.
3. Create military squads with a skeletal staggerd training cycle and put your non-miners/woodcutters into them.
-This puts haulers, crafters, and everyone not directly assigned to mining/woodcutting in armor/weapons for incidental fights, gives minimal training and raises general fighting skills/Discipline/Armor User
4. Setup long single wide approach corridors from the outside to your fortress, put cage traps, stone fall, weapon traps in the corridor.
-The Ballista arrow passes over the traps and doesn't strike triggered cage traps. Creatures that have been knocked unconscious, stunned, staggered or otherwise prone on the ground will not be hit.

5. At the entrance and exit of the long corridor put single wide corridors at 90 degrees to the long corridor and put doors in that corridor.
-This is an older methodology to prevent BD that is less than necessary for now until building destruction is more fully brought back into the game (currently the only BD's as far as I can tell are the fell and nightmare creatures). Building destructers require a 2 block charge to break a building/door etc. For ballista use it allows the ballista arrow to continue down the single wide corridor to the ammo catchments.

6. Ammo catchments. Same thing as for Archery Range. A flung/thrown/fired object that strikes a wall while occupying Open Space will fall down and not be destroyed. A properly made Ammo catchment along and at the end of a Ballista kill corridor means you can safely make Steel Ballista arrows w/o losing the arrow each time it's fired. This ALSO means you can essentially use a Ballista to raise Siege skill (I wouldn't recommend however, stick with the Catapults, they are inherently safer)

To build a "standard" ammo catchment into a kill corridor, Smooth and Fortify the walls along and at the end of the kill corridor.

On the friendly side of the fortifications, Channel a single wide trench. Have that trench be accessible from the inside but not the outside.

A Ballista arrow, fired down the kill corridor will either stay true to the single wide corridor or deviate. As it deviates it will fly through the fortifications and into the open space between the fortification and the rough wall. Once it strikes the rough wall, it will fall down the trench where it can be later retrieved and reloaded.

Ballista arrows have a maximum range.. theoretically? but its SO far that you might as well try to shoot at the moon, it's that far on a standard 4x4 embark.

The primary benefit of Ballista arrows is they multiple strike standing creatures and will continue through .. many many creatures unaffected/undeviated. A single Steel Ballista arrow can gib.. hundreds of creatures..

Don't plan on being able to shoot 2 arrows at the same set of enemies.. You might have that happen, but not with any measurable reliability. However, one thing you can depend on, is if you have a situation where you are able to fire 2 ballista arrows you will more than likely be able to fire more than just 2. You have an ammo stockpile close, there's arrows in it, the dorf firing the ballista is "assigned" to the ballista and will self task to reload and be prepared to fire/fire at will. So it is entirely possible to fire it more than 2 times during the same siege.

Adopting a long range methodology of using ballista makes them more usable. Shorter ranges require higher levels of Discipline. You can manipulate who uses the ballista based on Discipline. The key however is to use it as a layer of defense along with traps, doors, bridges, military squads and pathing trapped hostile creatures that you release during a siege.

[AlP]

Did you check the wiki on how they work?

https://dwarffortresswiki.org/index.php/Siege_engine