Description
WalkerSim transforms the way zombies and hordes behave in 7 Days to Die.
Instead of relying on random spawns, it runs a persistent simulation of zombie activity across the world.
In this system, zombies — referred to as agents — exist and move within a virtual 2D world that mirrors the actual game map.
These agents do not interact with the player or the game until conditions are right for them to be spawned, creating a world that feels much more alive and reactive.
How Does It Work?
At the heart of WalkerSim is a virtual 2D simulation that represents the loaded 7 Days to Die world.
When the game starts, WalkerSim generates thousands of virtual agents based on the map size and configured population density.
These agents roam the virtual 2D world by following simple, configurable behaviors. Examples include:
- Favoring roads and paths
- Grouping together in herds
- Staying near Points of Interest (POIs)
- Wandering freely based on environmental factors
Agents move constantly within the simulation, completely independent of whether players are nearby.
Only when they come close to a player will they cross into the real game world as actual zombies.
Below is a visual example of the simulation in action (sped up 16x for better demonstration):
Editor
You can fully customize the behavior with the included editor.
Documentation
You can find the full documentation here.
Important Information!
7 Days to Die changed the Mod API, for game version 1.4 use the version 0.9.7, and for 2.0 and newer use 0.9.8.
Changelogs
0.9.9
- Fix: Clients without admin permission can restart the simulation with the console command.
- Fix: Activation radius was too big causing issues with spawning.
- Fix: During spawn it could select the entity class
Nonewhich was substituted byZombiesAllwhich skewed the probabilities causing some classes to never spawn. - Fix: Pausing the simulation via command is not working.
- Change: Add option for the activation radius
SpawnActivationRadius, default is 96m. - Change: Added options to change the logging behavior, also log into a dedicated WalkerSim log file.
This version requires 2.0 (exp)
Previous Updates
0.9.8
- Change: Support for game version 2.0, older versions will not work.
0.9.7
- Fix: Allow clients with admin permission to run console commands such as
walkersim stats,walkersim showwill still only work on local games. - Fix: Incorrect calculation of the view radius, the spawn area was reduced by 50%.
- Fix: State persisting between games when playing single player causing unintentional problems.
- Change: Use 80% of maximum allowed zombies instead of 50%, 20% will be reserved for sleepers.
- Improve: Spawning logic now takes into account how many spawned zombies are near players preventing one player taking all spawn slots, better balances multiplayer games.
NOTE: For the game version 1.4 you will need to use version 0.9.7 and for 2.0 you need to use version 0.9.8.
0.9.6
- Fix: Editor crash trying to locate generated worlds.
- Fix: Condition that allowed to spawn more zombies than the game allows.
- Improve: When zombies fail to spawn the next attempt will be delayed as it will otherwise stall the spawn of other zombies.
- Improve: Better performance for the in-game preview using walkersim show.
- Change: Remove dependency to System.Drawing which eliminates the need to install libgdiplus on linux.
0.9.5
A new update has been released with some significant changes and bug fixes, so it is recommended to update. There have been also major improvements to the Editor, you can now zoom in and out of the preview making it easier to inspect the simulation. A new fine tuned default configuration, the previous one had a couple mistakes and this one vastly simplifies the behavior while getting more out of it. This version also fixes the bug where zombies when spawned would run or start digging, this should be mostly resolved now, it can still happen but should be rare. The spawning logic was also overhauled, before the code was nearly identical to how 7 Days to Die spawned hordes, the new logic attempts to keep the group as unique as possible while still respecting the biome data, there should be way less clones around now.
- Fix: The editor no longer resets the simulation when changing parameters.
- Fix: Some zombies were not despawned when getting too far away.
- Fix: Console help text was not correctly printed.
- Fix: Changing the World in the Editor does not update the preview.
- Fix: Zombies start running after being spawned.
- Fix: Zombies trying to dig when using
WanderforPostSpawnBehavior - Improve: Simulation is now fully deterministic.
- Improve: Using faster speeds in the Editor will now remain accurate, uses multi-threading.
- Improve: Default configuration has been updated for a more immersive experience.
- Improve: Change random distribution of POI’s, bigger POI’s will be prefered now.
- Feature: Added
SpawnProtectionTime, this disables zombie spawning when entering a new game for the first time. - Feature: Added
PostSpawnBehaviorwhich controls what agents will do once spawned in-game, right now limited toWanderandChaseActivator. - Feature: The Editor can now zoom in and out on the simulation preview.
0.9.4
- Fix: Zombie spawning now obeys tags of biome spawner.
- Fix: Zombies killed are removed from the active list, reducing excessive logging and correctly respawning zombies.
- Fix: Some agents were not updated depending on the population count.
- Improve: Reduce memory footprint and better performance by limiting the spawn queue.
- Improve: All players now have a chance to get zombie spawns, previously a single player could potentially exhaust the maximum allowed.
- Improve: Detection of where 7 Days to Die is installed, this is now obtained from Steam data.
0.9.3
- Fix: Flock processors always navigating towards the center.
0.9.2
- Fix: Support for version 1.2.
- Change: WalkerSim.xml configuration changed, old configuration files will no longer work.
- Change: Print a hint to the console when the local configuration does not match the one in the saved simulation.
0.9.1
- Change: Raise density limit to 4000 and max agents to 1000000.
0.9-beta.8
- IMPORTANT: The configuration MaxAgents is now replaced by PopulationDensity to better support multiple world sizes with a single configuration. The new configuration specifies how many agents per square kilometer, so the total amount of agents will be square kilometers multiplied by density, for example having density set to 160 and playing on a 6k map will be 6 x 6 x 160 which will be 5760 agents in total.
- A lot of fixes to the viewer. If you don’t see any Worlds in the Viewer that means it failed to detect your 7 Days to Die Install, this will be fixed in the next version.
- A couple bug fixes in the mod.
- Added new movement processors and re-organized them, existing configurations will probably no longer function correctly.
- Added walkersim stats console commands to print some information.
0.9-beta.7
- The simulation is now persistent which means that if a game is continued from a save file the simulation will be also restored.
- The viewer ‘WalkerSim.exe’ should be in a usable state now, you can now setup and preview the simulation and export the configuration.
- Fixed an issue that wouldn’t fast forward the newly created simulation when using TicksToAdvanceOnStartup
- Fixed custom sounds not being registered in the simulation.
- Changed how sound events decay, instead of decreasing the radius it has a duration and stays the same size.
- EnemySpawnMode is now respected, when disabled no zombies will be spawned.
- Added walkersim timescale <value> console commands to modify the simulation speed.
0.9-beta.6
- Fixed a performance issue.
- Implemented more functionality in the viewer.
0.9-beta.5
- Fixed exception when game is starting.
0.9-beta.4
- Fixed zombies not spawning near players that previously died.
- Respawning is now implemented, agents will respawn according the configuration of AgentRespawnPosition
- Added walkersim pause and walkersim resume console commands to pause/resume the simulation.
- Added detection to see if the client is the host and disables the mod accordingly, joining servers with the mod installed will no longer error.
Download
V2
DOWNLOAD for V2.0 (366 KB)
V1
DOWNLOAD for V1.4 (362 KB)
If you need help, you can use this support link.
Credits: ZehMatt
If you have any questions or have any problems/bugs, please use the support link (Discord, Forum Topic, GitHub Issues, etc.) in the post. If there is no support link in the post, please use the comments section.
This mod makes 7 Days to Die a true horror game
This mod has potential but it is way too hard to start a new game with it. It doesn’t scale, so you drown in zombies and enter an eternal battle where you fight-die-fight-die-fight-die and can’t progress the game because zombies arrive faster than you can kill them. Especially at night when you start to get ferals.
New game, first day was constant zombies with no relief. Cowered in a building overnight. Day 2, exited the building and was mauled to death by a direwolf. In the forest. Next to Trader Rekt. Respawned in the building, waiting til day 3. Exited the building: mauled by 12 feral zombies and a zombie bear. I don’t think this mod is for me.
Worked perfect on a rented “ping perfect” server until after a server restart. Then all open world zombies disappeared. Tried setting zombies and animals to 100/100 and restarting, tried reuploading the xml but no luck. Doing a “walkersim show” command works and shows Zom: 0 so definitely no zombies from the mod. Tried stopping the server, deleting the mod, starting the server, stopping the server, reinstalling the mod and still no luck. Don’t really want to fresh start.
Restart of world fixed it. Not going to do a server reboot again if I can avoid it.
I can’t seem to get this set up with any number of customizations or the configuration tool simply crashes. This seems like it has such potential but not being able to use the WalkerSim.exe is really hindering this… 🙁
It’s probably pointless to comment here because the author never seems to reply, but posting it here in any case.
The Discord link is invalid, the WalkerSim-Editor crashes when launched and the “walkersim show” console command does nothing. Oh yeah, and the 7dtd forum is offline.
I have this installed on a dedicated server running version 1.4(b8) of the game.
I have this running on a dedicated server with many other mods, And it works very well. Were all used to zombies that really don’t move around much. So this is an eye opener. Better get those base defenses built.
It was working fine, I have over 40 mods installed. But after I have modified one of my mods it’s not working anymore, there are no more wandering zombies in the whole map, just animals. There are only POIs zombies and Screamers spawning and propably blood moons zombies. but not even a single zombie wandering around.
How to stop them from respawning after killed?
This mod works in 1.2 well, but it seems like it might interfere with animal spawns, we haven’t seen any animals other than boars in pois. Other than that, it’s fantastic.
Balancing your overall zombies and animals counts worked for me. I’m set at 100/100 now, And it’s looking pretty good.
Interesting modification. And indeed, new zombies appeared that are not in random generation. Only it seems to work in one game session, since after restarting the program, new spawn points appear.
If someone does not display worlds in the program, then there is a solution:
You need to specify the path to the game in the registry editor. Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 251570 there should be a parameter called “InstallLocation”
The value of “InstallLocation” should indicate the path to the folder with the game. Example: C:\your path\7 Days To Die\
If you do not have a “Steam App 251570” section. Then you need to create it and add the “InstallLocation” parameter.
I’m always checking the site for an update, I’m exited on what you can bring. This mod has potential to be the best mod ever created. Good luck with your next update! I’ll be waiting 🙂
Sadly exe files are a no go for dedicated online servers. Does it need that file?
uuuuhhhh NEED MORE OF THIS PLZ
Is this mod compatible with Max Animals/Zombies and Claim Blocks , by KhaineGB?
how do you load a world into the Sim editor? i see how to import settings and stuff and change the seed but cant find where to import map so you can see roads and pois
Fun way to use this mod: Use mods that increase the general zombie population, set them all to walk speed, reduce their block damage to 50% or less, feral sense on ALL, and reduce the difficulty to under Warrior.
Hearing the smashing of the walls from all sides by 20-30 zombies while you desperately speed through a house collecting all the stuff is terrifying and high pressure. Being caught in that crowd means certain death for much of the game until you reach really high levels so you end up running more than fighting. I can sometimes get them into a chokepoint and slowly cut through their numbers over time, but I usually will run out of stamina or lose the ability to see past all the corpses so I end up running away anyways.
It also makes trader stops more interesting. You can literally hear them at the gate doors and sometimes they pop over the fence and enter the area. It’s damn scary to open the door, thinking you were perfectly safe, and be jumpscared by a zombie you couldn’t hear because there are zombies surrounding you constantly.
I had to reduce the zombie sounds a bit but overall, it gives me the feeling of living in in a Romero film universe.
I was killed in an ocean of zombies at one point and it was genuinely scary. Very fun.
Works well, but when using with the NPC Mod, no zombies spawn in the wasteland, snow or desert biomes. I had a bunch (20 or so) Harley NPC’s come out from behind the Crack a Book Cafe in the snow biome and had to run for my life.
On the latest Beta 5, my game freezes whenever I shoot a zombie with random guns and almost halts to a stop when using the WalkerSim show command.
I had Izayo’s AIO gun pack so I suspected of it to have been the cause but before removing it, I removed WalkerSim just to make sure it wasn’t the AI but it stopped freezing after removing WalkerSim. It’s probably due to the CPU processing things and perhaps even incompatibilities with other mods. My last suspect would be just a slow processor but I’m no expert so I can’t say but for reference sake, I am on a laptop, with Intel i7-10750H.
I don’t think the log would be of much help here since there was nothing unusual, just slowdowns. But I just wanted to report on things. Do tell me if you want the log though.
I’ve tried everything and can’t get it to work. It says I’m missing dependency an I tried ur solution but still nothing so guess I’m doing something wrong.
LOL why is there an .EXE in that zip?
To run the simulation window
Seems like this may clash with other horde mods. I had this installed with a few others, namely Improved Hordes, EXTRA Mob Spawns 2x 4x 10x, and Return of the Hordes. This combination meant wandering zombie spawns were very rare, I could see them via the ‘walkersim show’ console command, but it didn’t seem like they were spawning.
I had the same experience. Would love to work with you on increasing zombies in the game and comparing notes on what mods we have installed.
It works really well, only annoyance i personally have the spawning of more zombies is a bit too close to the location of the player. And i dont know if its the mod but when i took over a house even when crouched and at 1% visibility the zombies knew where i was. No other mods installed and no feral sense was on. Maybe i just had bad luck.
Doesn’t seem to work or do anything, nothing compared to the video anyways. Might be conflicting with one of my other mods, I have around 30 mods LOL.