Sappers, what makes them do the things that they do?

[IHateTheReportSystem]

So in my latest play through I did the standard 'add a ♥♥♥♥♥♥♥♥ of turrets surrounding everything that isn't your kill box and then turn them off'. This worked for a bit, but now raiders are showing up with sappers making me think the turrets and decrease of sappers were unconnected. Its just a pain because 60cm shells take up alot of steel, however I would prefer if raiders readily showed up to be mowed down, how can I fix this? Also while your here do you know any 'vanilla like' mod that adds a tonne of research, I ran out of options.

[Estranged]

Sappers in general look for the wall sections with the least resistance in terms of turrets in the area and thickness of walls. If you have an area uncovered by turrets or the least amount of them, they will usually go there unless the wall is very thick compared to other places. There are videos explaining this in more detail on youtube.

As for research, just add some of the 'Vanilla Expanded' mods that you find interesting. Most things they add need to be researched.

[di eshor ribly]

In a nutshell, sappers pick the shortest route to your base and dig their way through. If they have siege axes (600% block damage) they tear through walls and mountains with ease. They still do not cross deep water (I use a terraforming mod to give myself a moat surrounding my base - I only have one entrance in or out). Your average raid picks the path of least resistance, taking the turrets into account. This is why the open path leading into your killbox works like it does: despite the defenses it's the easiest route.

Termite mechanoids pick a route and work like the sappers with the axes, except their Thumper Cannons literally and without exaggeration delete walls. They should be your priority target whenever they show up... but they're also kind of weak. A single melee pawn will tie them up until they die.

[dande48]

What I recommend doing is, if you can kill the first sapper raid before they've tunneled too far, go into that tunnel and place a bunch of traps. The sappers will usually take the same "path" to try to tunnel into your base, and will usually die to those traps (steel are the best).

As for the mechanoid sappers... You'll just have to use zeushammers (or EMP, if you don't have royalty).

[Blazikasu]

They'll target a colonist bed and search for a direct path that doesn't get them murdered by turrets, without any care for how many walls they have to destroy to get there. You can lure them in by leaving a small path/corridor or whathever zone that's unprotected by turrets (or with walls that block the LoS of the turrets to said path they will take) that leads to your colonist's dwellings. The sapper AI will recognize that path as safe and the sappers will happily make way into your base thru that "safe path". Now, because it doesn't account for stuff like traps, you fill their safe path traps, and get some cover for your pawns to shoot at the sappers. Basically it's a secondary turret-free killbox to abuse sapper AI, it'll be weaker ofc but sapper raids are weaker than normal raids so it works out just fine. Also please don't forget to wall out that sapper trap, you want only sappers going thru there, not normal raiders.

Breach raids are different than sappers tho, and I'm not confident enough on my knowledge of it's AI yet to give you a definite answer on how to handle them, I just have some random cover spread around the map and bum rush the rude breachers before they level my map.

[Fortus Victus]

Remember with traps though, you get 1 free use with a given faction, after that they avoid that area in any following raids as well. Game has come a long way

[IHateTheReportSystem]

Aight, thanks for the help, the area the always burrow into is a space I dont really use anyway so I should be able to set something up.