Advice on Wall Defense

[Stephen of Blois]

I am creating a basic wall defense. The screenshot shows flamethrower turrets about 16 wall blocks from wall and the gun turrets are about 7 wall blocks from the wall. Wondering if this looks like it will be effective.

https://steamcommunity.com/sharedfiles/filedetails/?id=2871653086

[Jagdtiger]

Generally, you want to minimize the exposure of your walls to enemy attacks, since repairing/replacing walls is generally more expensive than bullets, and significantly more expensive than oil. For this reason, it is usually better to place your turrets 1 tile away from the wall, to maximise the exposure time of approaching biters (the 1 tile gap is to prevent spitter splash damage). On top of this, perhaps the most important part of a base's wall is an external protection called "dragon's teeth". Essentially, place walls in a grid like pattern infront of your wall. This slows biters approaching, but doesn't block them, so they wont attack the teeth. From my testing, the best arrangement of teeth is placing them 1 tile apart parallel to the wall, and place 3-6 ranks of teeth 2 tiles apart, offset by 1 tile each. This style of defence is more than sufficient for even the most extreme worlds of vanilla factorio

[Stephen of Blois]

Originally posted by Jagdtiger:

Generally, you want to minimize the exposure of your walls to enemy attacks, since repairing/replacing walls is generally more expensive than bullets, and significantly more expensive than oil. For this reason, it is usually better to place your turrets 1 tile away from the wall, to maximise the exposure time of approaching biters (the 1 tile gap is to prevent spitter splash damage). On top of this, perhaps the most important part of a base's wall is an external protection called "dragon's teeth". Essentially, place walls in a grid like pattern infront of your wall. This slows biters approaching, but doesn't block them, so they wont attack the teeth. From my testing, the best arrangement of teeth is placing them 1 tile apart parallel to the wall, and place 3-6 ranks of teeth 2 tiles apart, offset by 1 tile each. This style of defence is more than sufficient for even the most extreme worlds of vanilla factorio

Thank you. I was afraid to move the gun turrets closer because of spitters, etc destroying the turret, but I see your point and will move them. I like the dragon teeth idea and may take time to place those down.

[juliejayne]

Dragons Teeth are cheap and effective. Personally I would keep the turrets 2 or 3 spaces from the wall. Feed the turrets from a conveyor belt behind them.
Flamethrowers behind the ammo belt. Connect the oil for the flamethrowers with a pipe behind them and spur off to each flamethrower. Never daisy chain oil through the flamethrowers. If one gets taken out your whole defence line dries up. Biters tend to attack the weapons not the pipes.

I hope that makes sense.

[knighttemplar1960]

I'll give a bit of a different response.

Gun turrets have a range of 18 tiles.
Laser turrets have a range of 24 tiles.
Flame thrower turrets have a range of 30 tiles with a minimum range of 6 tiles. This makes it possible to layer turrets with gun turrets in front and belt feed ammunition with inserters with laser turrets behind that and flamethrowers behind that.

Small and medium biters have an attack range of 1 tile.
Large and behemoth biters have an attack range of 2 tiles. This means that you want a one tile gap between your inside wall and your turrets. If you put them up against the wall the biters can damage the turrets through a single tile of wall.

This means that I place walls one tile away from the gun turrets and I make it a double thick wall.

Small spitters have a range of 13 tiles.
Medium spitters have a range of 14 tiles.
Large spitters have a range of 15 tiles.
Behemoth spitters have a range 16 tiles.

I don't use dragons teeth any more as they are much too time consuming to lay out by hand. Instead I use a 2nd double outside wall. The outside edge of which is 17 tiles away from the gun turrets. This allows the gun turrets to hit biters but remain out of range of even behemoth spitters (unless the biters break through the outside wall and allow the spitters to get close enough to hit the turrets).

Neither biters nor spitters can hit your turrets though you can hit them so you "can" (but shouldn't) chain as many flamethrower turrets as you want even down to minimum fluid flow levels since a flamethrower turret holds 100 oil and that allows it to fire for 33 seconds

A wall tile costs 4 bricks. A magazine of basic ammo costs 4 iron plate so they are the same cost. A basic magazine can kill a small biter in 2 shots but it takes 10 shots (or the entire magazine) to kill one medium biter. As soon as you are up against medium biters or tougher walls are cheaper than ammunition so its OK to slather walls on thick. Repairing damaged walls is time consuming. Replacing destroyed wall blocks is quick. Early game (pre-bot) its much faster to ignore damaged blocks when making a repair run and just replace destroyed blocks since you can just click and drag or click and run along the wall.

[Jagdtiger]

Originally posted by knighttemplar1960:

I'll give a bit of a different response.

Gun turrets have a range of 18 tiles.
Laser turrets have a range of 24 tiles.
Flame thrower turrets have a range of 30 tiles with a minimum range of 6 tiles. This makes it possible to layer turrets with gun turrets in front and belt feed ammunition with inserters with laser turrets behind that and flamethrowers behind that.

Small and medium biters have an attack range of 1 tile.
Large and behemoth biters have an attack range of 2 tiles. This means that you want a one tile gap between your inside wall and your turrets. If you put them up against the wall the biters can damage the turrets through a single tile of wall.

This means that I place walls one tile away from the gun turrets and I make it a double thick wall.

Small spitters have a range of 13 tiles.
Medium spitters have a range of 14 tiles.
Large spitters have a range of 15 tiles.
Behemoth spitters have a range 16 tiles.

I don't use dragons teeth any more as they are much too time consuming to lay out by hand. Instead I use a 2nd double outside wall. The outside edge of which is 17 tiles away from the gun turrets. This allows the gun turrets to hit biters but remain out of range of even behemoth spitters (unless the biters break through the outside wall and allow the spitters to get close enough to hit the turrets).

Neither biters nor spitters can hit your turrets though you can hit them so you "can" (but shouldn't) chain as many flamethrower turrets as you want even down to minimum fluid flow levels since a flamethrower turret holds 100 oil and that allows it to fire for 33 seconds

A wall tile costs 4 bricks. A magazine of basic ammo costs 4 iron plate so they are the same cost. A basic magazine can kill a small biter in 2 shots but it takes 10 shots (or the entire magazine) to kill one medium biter. As soon as you are up against medium biters or tougher walls are cheaper than ammunition so its OK to slather walls on thick. Repairing damaged walls is time consuming. Replacing destroyed wall blocks is quick. Early game (pre-bot) its much faster to ignore damaged blocks when making a repair run and just replace destroyed blocks since you can just click and drag or click and run along the wall.

The point with the price is that, excluding flamers, the ammo has to be spent regardless, wheras the walls only have to be rebuilt/repaired if you let the biters attack them (which is more likely with the double wall design). This is doctrinally consistent with maximising the usage of flamers, due to the abundant nature of oil, by holding the biters in the flames as long as possible with the double wall design. However, while the flamers do save resources in this way, it is at the cost of the walls being hit much more, which overall increases resource drain as time goes on with bigger biter waves and your guns needing to come into action more often. But of course, in late game mega+bot bases, the resources spent on defence are negligible, but the double wall design fails in absolute defence, since a large swarm (100+ behemoths) can simply rip through the first wall without the funnelling of the dragon's teeth, so i would argue that for late game, the dragon's teeth are a safer bet.

Though this wall design certainly does have more merits in early game due to the reduced resource consumption, i think that it is still flawed because of automation. You can automate brining ammo to the guns with belts, but you cannot automate rebuilding/repairing, which you will need to do more by blocking them in with the second wall. By building 3 layers of dragon's teeth around the time of fluid processing, usually only the first 1 or 2 layers are destroyed or worn down by the time i have launched a rocket with no maintenance. For this reason, i'd argue that the double wall design is suboptimal compared to designs which focus on preventing biters attacking, rather than more efficiently organising the distribution of used ammunition resources.

Other than that, i agree with the spacing of turrets behind the main wall, and that the main wall should be 2 tiles thick, which i originally neglected to mention

[Barnaby]

Originally posted by NERV HQ:

The drill has already breached the second layer of armor plating.
It's boring through the third layer as we speak.
There are 22 Kakumo-type armor belts.
Estimated time of final breach through all 22 layers is 00:06:54 tomorrow.
That's 10 hours, 14 minutes from now.

more layers of wall = more winning

[AlexMBrennan]

I don't use dragons teeth any more as they are much too time consuming to lay out by hand. Instead I use a 2nd double outside wall.

I don't think that this makes optimal use of your flame turrets because they are an AOE weapon which works much better when chokepoints force the enemies to stand close together. If there are no natural chokepoints then it would be a good idea to create them.

[knighttemplar1960]

Originally posted by Jagdtiger:

The point with the price is that, excluding flamers, the ammo has to be spent regardless, wheras the walls only have to be rebuilt/repaired if you let the biters attack them (which is more likely with the double wall design). This is doctrinally consistent with maximising the usage of flamers, due to the abundant nature of oil, by holding the biters in the flames as long as possible with the double wall design. However, while the flamers do save resources in this way, it is at the cost of the walls being hit much more, which overall increases resource drain as time goes on with bigger biter waves and your guns needing to come into action more often. But of course, in late game mega+bot bases, the resources spent on defence are negligible, but the double wall design fails in absolute defence, since a large swarm (100+ behemoths) can simply rip through the first wall without the funnelling of the dragon's teeth, so i would argue that for late game, the dragon's teeth are a safer bet.

Though this wall design certainly does have more merits in early game due to the reduced resource consumption, i think that it is still flawed because of automation. You can automate brining ammo to the guns with belts, but you cannot automate rebuilding/repairing, which you will need to do more by blocking them in with the second wall. By building 3 layers of dragon's teeth around the time of fluid processing, usually only the first 1 or 2 layers are destroyed or worn down by the time i have launched a rocket with no maintenance. For this reason, i'd argue that the double wall design is suboptimal compared to designs which focus on preventing biters attacking, rather than more efficiently organising the distribution of used ammunition resources.

Other than that, i agree with the spacing of turrets behind the main wall, and that the main wall should be 2 tiles thick, which i originally neglected to mention

Once you get to megabase and bot levels the 100+ behemoth scenario does not occur. Once you have cleared the territory and have artillery, when an expansion occurs your artillery fires and destroys the spawner and any worms and might activate 6 or 7 (damaged) bugs.

With bots, trains, and the circuit network you can automate exterior repairs, replacements, ammo, artillery, and oil.
https://steamcommunity.com/sharedfiles/filedetails/?id=2617194066
https://steamcommunity.com/sharedfiles/filedetails/?id=2617193679
With spidertrons you can build by remote. With infinite researchs you can increase your damage so much that bugs are dead before they can do more than ding your walls and your construction bots repair it immediately.
https://steamcommunity.com/sharedfiles/filedetails/?id=2602877802
Contrary to the above post dragon's teeth aren't immune to attack nor do they confer immunity. Only a single biter can occupy one tile at a time (2 tiles for large and behemoth). If biters behind can't path around the dragons teeth and the biters in front, the rear biters will attack the dragon's teeth. Replacing and repairing those pre-bot is extremely time consuming. The time I save just laying out double walls pre-bot more than makes up for the extra walls and repair packs that it costs.

Originally posted by AlexMBrennan:

I don't use dragons teeth any more as they are much too time consuming to lay out by hand. Instead I use a 2nd double outside wall.

I don't think that this makes optimal use of your flame turrets because they are an AOE weapon which works much better when chokepoints force the enemies to stand close together. If there are no natural chokepoints then it would be a good idea to create them.

The outside wall becomes its own choke point. Biters can't occupy the same tile at the same time. They either wait behind biters being destroyed or spread out laterally where other walls stop them and other turrets take them out. With layered turrets all 3 types concentrate fire just on the other side of the exterior wall and the flamethrowers keep pouring damage on to that spot.

I've tried dragon's teeth.

I've tested pop up choke points.
https://steamcommunity.com/sharedfiles/filedetails/?id=2172726952
https://steamcommunity.com/sharedfiles/filedetails/?id=2172727164
https://steamcommunity.com/sharedfiles/filedetails/?id=2170792185

Pop up Death traps
https://steamcommunity.com/sharedfiles/filedetails/?id=2526366398
https://steamcommunity.com/sharedfiles/filedetails/?id=2526366524

and the double wall.

The double wall is the fastest set up pre-bot. It works adequately, is fast to rebuild/replace pre-bot, and I always have far more stone than I ever can use. I can't remember a game that I tapped more than 2 stone sources beyond the start patch. The double wall lets me get back to building and expanding faster than any other system which is more important for me pre-bot and becomes moot with infinite researches.

[AlexMBrennan]

They either wait behind biters being destroyed or spread out laterally where other walls stop them

Is that what you want? Surely ten flamethrowers focusing fire on a chokepoint all enemies have to pass through is better than spreading out the damage over a wide area where fewer enemies will be hit by each attack.

[knighttemplar1960]

Originally posted by AlexMBrennan:

They either wait behind biters being destroyed or spread out laterally where other walls stop them

Is that what you want? Surely ten flamethrowers focusing fire on a chokepoint all enemies have to pass through is better than spreading out the damage over a wide area where fewer enemies will be hit by each attack.

It works. What I want is to stop biters (and spitters) from reaching my turrets (and factory). This does exactly that. If the bugs are moving to get to a spot where they can attack they aren't causing any damage and my turrets are firing while they move. It might cost a few more resources in terms of stone to build wall which is more abundant than I can use even on minimum settings. Oil depletes but never runs out so I can always fuel flame throwers. Once I have nuclear power (and later on vast arrays of solar) laser turrets are essentially free and the fraction of my production ammunition takes compared to science pack demand is minuscule. Any damage that does occur is spread out over a larger area instead of concentrated in the area of a choke point where a hole in the defense may be created by constant attacks. If the biters manage to poke a hole in the outside double wall they create a choke point for me at that location. I just have to get out there and make repairs before they can breach the inner wall.

The benefit for me is that it takes a fraction of the time to set them up pre-bot (especially for me since my motor control is bad) that dragons teeth set out by hand does. If I'm in a race against evolution speed, that pre-bot time is much more valuable to me than a few extra walls particularly when I have wall production automated and especially when the exterior wall I'm setting up is temporary and will be removed when I need the space to build. I can just click and run, click and run, click and run, click and run and walls are set up for a large swath of defense and all I have to do then is set out turrets and ammo supply and click and drag power poles to supply electricity to the inserters and pumps. I all ready have trains and combinators by then so a 2 car train, one carrying ammo and the other oil, making deliveries from a spur off the main rails is a matter of a minute or so. Pre bot repairs consist of riding the ammo supply train out to the hard hit areas and replacing the destroyed walls with a click and drag once every 20 or 30 minutes.

By the time I have bots I have layered defenses and using dragons teeth or double walls is pretty much moot. At that time I have trains automated with defense supplies for permanent walls and outposts and production chains to produce defense supplies is automated and pretty much forgotten. I could switch back to dragons teeth at that point (and I still have my early dragons teeth blue prints) but by that time there is no point. Bugs aren't getting through even when I start clearing out huge bunches of nests with artillery and causing huge swarms of retaliatory waves. The bots fix things as they break at that point in the game and once the initial artillery clearing is done there are no more large swarms to worry about.

The OP can take from that what he wants. I suspect that if its easy for me its going to be easy for other players too.

I found this video of a player testing various dragons teeth designs and, without doubt, they work but pre-bot they are impractical to set out until you have bot speed research maxed out, particularly for me.
https://www.youtube.com/watch?v=hM2YThrpq0U

[Jagdtiger]

Dragon's teeth are no harder to set up than placing an inserter into every furnace in an array manually, and save significant resources in the early game, while also having an overall greater ratio of protection:wall (i.e bot time) in the endgame. Plus, dragon's teeth realistically never have to be repaired. In my 400 hour death world factory, my oldest rows of dragon's teeth are 6 layers deep and around 200 hours old, with no artillery support in their district, and i never even bothered to set up bots for them, yet only 2 layers are completely destroyed, leaving 4 layers of teeth left, and the main wall is virtually unharmed. In my mind, teeth will always be superior as a unique auxilliary defensive device, and should only be augmented with a second wall, not the other way around, which is only relevant for modded worlds

[Stephen of Blois]

Wow. Thanks everybody for all the help. I still need to read and study it. I really appreciate it. May have some questions later.

[knighttemplar1960]

Originally posted by Jagdtiger:

Dragon's teeth are no harder to set up than placing an inserter into every furnace in an array manually, and save significant resources in the early game, while also having an overall greater ratio of protection:wall (i.e bot time) in the endgame. Plus, dragon's teeth realistically never have to be repaired. In my 400 hour death world factory, my oldest rows of dragon's teeth are 6 layers deep and around 200 hours old, with no artillery support in their district, and i never even bothered to set up bots for them, yet only 2 layers are completely destroyed, leaving 4 layers of teeth left, and the main wall is virtually unharmed. In my mind, teeth will always be superior as a unique auxilliary defensive device, and should only be augmented with a second wall, not the other way around, which is only relevant for modded worlds

The OP clearly isn't setting up defenses for a death world. My personal preference is to use the time that I would be manually setting up dragons teeth to manually set up furnace arrays instead (since I must do that any way). This saves the time of manual teeth placement and allows me to increase my tech faster, increasing my damage, shooting speed, available weapon types, and mining production faster than the bugs evolve.

Death world settings are clearly a different situation. With my motor control issues I'll never manage a death world or a speed run. The OP is clearly just getting started in the game and doesn't have the experience you or I have gained over long hours of play time to build quickly without having to think about exactly what needs to be done next. For a new player the time spent setting up dragon's teeth may mean that you are getting over run on the other side of your base or the bugs evolve before you have the tech to handle them. (Both of which happened to me early in my Factorio experience).

Double walls are simply another option. They are quick and easy to set out and repair. If they didn't work I would never have been able to build a mega base on default settings. The OP can decide for himself what works best for his play style and level of experience and it is better to have more options and information than less. You can try various set ups and see which works best for you and when you land on one that works you can reload a previous save and continue on from there.

[Stephen of Blois]

I used to set up belts with ammo to feed the turrets, but later I started to be more aggressive with hunting down nests, etc and could wait until I got requester chests and then fed all my wall turrets with them. It seemed to work fine, but wondering if that is a reasonable option.

I never considered the problem of daisy chaining the flamethrower turrets - this is good to know.

[knighttemplar1960]

When your base gets larger and UPS issues start to become a problem you want to use bots only where you absolutely need them. Lost of bots can be a large drain on UPS.

For daisy chaining flamethrower turrets each turret counts as 1 entity. Each turret holds 100 oil and that 100 oil allows it to fire for 33 seconds. Minimum flow for fluids with 1,000 or more entities is 230 per second. At that fluid flow rate it would take 434 seconds to fill 1,000 chained flame throwers but you are never going to have a situation where you will have all the flame throwers in that chain empty. At 230 per second you can continually keep 70 flamethrower turrets supplied even if they never stop firing. Depending on your settings when you set up the game you'll never have that happen. The flow rate for 100 chained entities is fast enough to keep them all 100 charged faster than they can fire if all the entities are flamethrower turrets. A chain of 200 will keep half of them fully charged if they fire full time.

https://wiki.factorio.com/Fluid_system