7 Days To Die Heatmap

Overview

In the 7 Days To Die world, one of the mechanics that affects zombie spawning is the Heatmap level. Now, it is not something that is literally linked with the temperature. But rather, the Heatmap level represents the amount of activity in a particular area. The higher the activity in a certain area, the higher will be the heatmap level in that area as well as adjacent areas. This will lead to more zombies being spawned nearby.

Every 16 x 16 block area, also called a chunk, has a heat level value attached to it. There are certain activities that can increase the heatmap level. This affects not only the chunk in which the activity is happening but also in adjacent chunks as well. When the activity causing the increase in heat, stops, the heat level gradually decreases over time.

The Heat level is measured on a 100% scale and it is always going up or down based on the amount of activity in the chunk. In order to check the heat level of the chunk your character is in, activate debug mode and press on F8 two times.

How Does Heatmap Affect Zombie Spawning

Since heatmap represents the amount of activity in a chunk, if a player engages in certain activities like using the forge, felling too many trees etc, then the heatmap in that area will go up. If the activity level is high enough, then the heat will be set to about half the max value and it will trigger an event near the chunk where the activity is happening. And by even we mean, that zombie spawning will happen and they will start towards the source of the heat.

The higher the heatmap value the greater chance that it will lead to zombie spawning. You have to watch out for the following zombie types when there’s too much activity going on:

Scouting Zombie

In the earlier versions of the game, scouting was the job of the Spider Zombie. However, now that job is undertaken by the Screamers. These pesky zombie ladies will immediately start wandering upon spawning towards the area emitting the heat.

If they spot you or any other player, then of course the Screamer will give out a shrill scream. And soon you will have a handful of zombies to deal with. If you don’t take out the screamer soon enough, then you might even have to deal with zombie hordes! There’s another reason to take out the screamer as quickly as possible. And that is, if the screamer doesn’t spot a player, then it will just storm towards and spawn zombies to attack the item generating the heat.

Pitstop Horde

Pitstop hordes are a very destructive bunch. They kind of behave like wandering hordes, except that these get spawned only when the heatmap gets reset too frequently. The Pitstop Horde’s difficulty level also depends upon how many times the heatmap got reset. This can get real troublesome, especially if the Special Infected zombie has been spawned in the Pitstop horde.

The wandering horde just randomly wanders about till it comes upon a player. The pitstop horde, on the other hand, will immediately go for the item emitting the heat. So if it’s a workstation, forge, chemistry station or even the campfire, the pitstop horde will move in and try to destroy these items. Note that a Pitstop horde may also contain screamers that attract other zombies. Also, the pitstop horde does not get spawned during the blood moon, if that’s any relief!

How Is The Heatmap Affected By Different Items

Different items generate heat events when active. Heat is generated through these Heat Events, which are discreet “packets” that define its different attributes such as strength, lifetime etc. For example, if you light up 2 campfires and keep it on for 45 minutes in game-time, then that will create 2 heat events with a total heat value of 10%(check table below). This is because each campfire can create only one event of strength value 5 in 45 minutes.

Blocks That Generate Heat

Block

Strength

Frequency

Lifetime

Max Heat[3]

Campfire

5.00

1000

5000

25%

Forge

6.00

1000

5000

30%

Workbench

2.00

1000

5000

10%

Cement mixer

2.00

1000

5000

10%

Chemistry station

5.00

1000

5000

25%

Torches

1 see below

~666 see below

4000

see below

Candles

0.5 see below

~666 see below

4000

see below

Burning Barrels

1 see below

~666 see below

4000

see below

 

Breaking Down An Heat Event

  • Strength: This is how much ‘Percentage of heat event’ that this block will generate.
  • Frequency: This is the number of ‘ticks’ before the next heat event is created (see below).
  • Lifetime: This is the total number of ‘ticks’ after which the current event expires.
  • Max-Heat: This is the total heat that this block will create during its Lifetime.


Note: As soon as the block get active, it creates the first heat event. The next heat event is created after the frequency timer as mentioned above.

What are Ticks?

Ticks are a unit that each block uses to calculate the time between each heat event, and for how long an event lasts. This is what is used to calculate the Frequency and Lifetime of each heat event. In the 7D2D world, 1000 ticks = 1-hour in-game time. So the duration of a tick in real-time really depends on your game settings. If it’s at the default setting of 60 min/day, the one tick equals 3.75 seconds.

Here’s an example…

Let’s say you have two forges running simultaneously with no other heat source in the chunk. As per the table shown above, each forge has a strength of 6 and a frequency of 1000 ticks. This means each forge will generate 6% heat every hour in the game.

Now if you want to calculate the heat in the chunk after 2.5 hours, it would be calculated as follows:

Chunk Heat =  Heat Strength X Number of Events X Number of Items = 6 X 3 X 2 = 36%

The Forge has a lifetime of 5000 ticks, which equals 5 hours in-game time during which it will reach the max heat level of 30. So after say, 8 hours, the total heat in the chunk due to the 2 forges would be 30 X 2 = 60%. If the forges remain active and no additional heat source is introduced in the chunk, then the chunk heat level will remain steady at 60%

Heat Dissipation

There tends to be some confusion on how the heat level dissipates. This is due to two contradicting statements in the file “stealth.xml” and “blocks.xml”. In the first file, it states that the Heatmap time is “the time in seconds it takes for the heat to dissipate. Dissipation is not modelled, it’s instant off after the time limit.”  However in the Blocks.xml file, it states that  “HeatMapTime decays in x seconds, and scales with game time”.

Lots of people misinterpret this latter comment to mean that the Heat dissipates gradually over time. However, this is not true. Heat dissipates immediately when its lifetime expires. What the comment in the Blocks.xml refers to is applicable only to Candles, Torches and Burning Barrels. These follow a different set of rules for optimisation purposes. You can find more info on this below.

What Are Flickering Fires?

Flickering fires include Candles, Torches and Burning Barrels. When these items are placed they too affect the heatmap. However, note that flickering fires that are part of the prefab do not emit any heat. Also, the heat event mechanism works differently for flickering fires compared to the blocks mentioned earlier.

Flickering fires generate heat events every minute in real-time. This behaviour is probably intended for better performance. As per the table above, flickering fires should generate heat events every 666 ticks.

But that is not easy to calculate and of really of not much use. It’s better to remember that, candles emit half the amount of heat as Burning Barrels and Torches. So if you don’t want to be attracting too many zombies to a particular place, like your base, it is better to use candles for light.

For example, At the default setting of 60 mins per day, one torch generates .5% heat event every minute in real-time. So, if you put up 10 Torches, after 20 minutes it would generate 100% heat. On the other hand, if the default setting is changed to 120 mins per day, one torch would only generate .25% heat. Hence, 10 torches will need 40 minutes in real-time to reach 100%

How To Generate Maximum Heat

Well, what if you feel like taking down a lot of zombies? In that case, you want to generate maximum heat which will attract a lot of zombies towards it. In the early game, you can do this just by using campfires. Of course, you need a lot of campfires. For example, 25 campfires loaded with max wood

If you are looking to purposely generate as much heat as possible, and draw the maximum amount of zombies to a specified area, then 25 campfires fully loaded with wood will quickly reach and maintain the heat map at 100%. Once it reaches max heat, you can even switch to 5 of the campfires, as they are not needed anymore to maintain the heat at 100%

During advanced stages of the game, the auger will do the trick of generating max heat much faster. Just 100 rounds from an auger will spawn a screamer somewhere nearby. Since the auger has an average RPM of 300, it can spawn 3 screamers every minute.

How Using Items Affect The Heatmap

Weapons like explosives and firearms create heat every time it is used. The table below shows how different items emit heat when you interact with them.

 

categoryTypeExamplesheat (%)Lifetime
toolsStarting Power toolsStarting up (but not continuing to use) the auger or chainsaw190
gunsMost Silenced G1 weaponsSilenced pistol or mp50.4180
gunsG1 weaponsPistol, dessert vulture,mp5,m60 and most turrets0.65180
gunsMost Silenced G2 weaponsAll rifles except hunting, ak47.0.65180
gunsG2 weaponsAll rifles, ak47 and tactical assault rifle.0.9180
gunsThe .44 magnumJust the .44 magnum0.75180
gunsFull ShotgunsAll Shotguns except saw-off1180
gunsSilenced Pump ShotgunJust the silenced pump shotgun0.8180
gunssawn-off shotgunJust the sawn-off shotgun0.3120
gunsSilenced hunting rifleJust the hunting rifle0.6180
gunsSilenced m60Just the m600.7180
gunsminor turretsThe junk turret (and what appear to be an unused sound)0.25180
gunsRocket launchersJust the m136 rocket launcher0.290
explosivesMolotov cocktailJust the molotov cocktail explosion0.290
explosivesAll other explosivesAll Explosives except the molotov cocktail5300
miscshooting metalEvery bullet regardless of the type that strikes a metal block (this is particularly bad with machine guns due to the number of bullets they fire)0.160
miscOperating drawbridgeOpening and closing the drawbridge0.290
miscLarge creatures DeathsThe death of most creatures as big as a boar and up fall in here (Though zombies do not seem to be included)[4]0.290
miscTraderAll trader calls (such as announcing that their shop is open)0.290
miscminor soundsA huge number of minor sounds have a heatmap entry though the amount is so small they can be ignored a full list of sound file names is hidden in a collapsed cell below. They are mostly sounds that occur when looting however things like the blade trap hitting something and the dart trap shooting are also in the category.0.0560

 

How Interacting With Nature Affects The Heatmap

There are many occasions when you will be dealing with nature in order to gather resources to survive. One of the most common resources you need in the 7D2D world is wood. And while chopping off a couple of trees won’t really matter too much, clearing an entire block of trees will definitely get the attention of zombies. Especially so if you use tools that make a lot of noise such as a chainsaw. 

Similarly, a lot of digging and mining activity will emit enough heat to attract zombies towards you. And if you’re using an Augur to do dig and gather resources, well then you better be prepared for a little battle against the zombie horde which you are sure to attract.

Hunting animals using firearms will increase the heat in the chunk and eventually attract zombies. However, if you use quiet weapons such as the Bow, it won’t affect the heatmap. Farming activities, also don’t affect the heatmap.

How Do Glass & Metal Objects Affect Heatmap

Metal objects, obviously, tend to make noise. Especially if you are trying to destroy it using another metal object such as a Wrench. Apart from noise, such activity will also generate heat events. In the case of a wrench, each hit increases the heat by 0.1 with a lifetime of 60 ticks.

If you use a tool that has higher block damage, the overall heat generated will be comparatively less, since you will hit fewer times. However, trying to break open a tough object such as a Safe will generate a lot of heat. This is because Safe’s tend to be very durable, will require a lot of bashing before it breaks. On the other hand, using a lockpick is a heat-free way to open a safe!

Note that, even if zombies attack metallic objects, it will generate heat. You should keep this in mind when building structures using steel etc. Although more resilient, metal structures might end up attracting more zombies. That is one of the strategies is to use a more flimsy material for the outer layer of your structure.

In Short, most interactions with metal and glass objects will increase the heatmap value. This includes constructing and also upgrading blocks using metal such as upgrading a block or wooden door to metal.

Heat Due To Breaking blocks

The table below gives detail of heat generated by destroying different block types.

Material

Strength

Lifetime

wood

0.6

60

stone

0.25

45

metal

1.42

90

glass

1.5-2.1

90

Compounding Effect Of Heatmap

You’ve seen so far how different actions and blocks generate heat. Each of these activities individually adds to the total heat of the chunk. So for example, if your base has a workbench, a couple of forges and 3 campfires running, then the heat generated from each of these items will have compounded effect on the heatmap. Even a single heat emitting item is active for a long time, then it will eventually reach generate a lot of heat.

Now, heat events once generated, take time before decreasing and eventually dying out. But during this time it’ll attract zombies, and there will be a small battle. If there was heavy use of firearms, then this killing all those zombies will also generate considerable heat, enough to attract more zombies. This can be a tough cycle to get out of. And, that is why you should also be aware of horde mentality.

How Heatmap Affects Horde Mentality

Do you have a tendency to take shelter in just one place? Then you may have to take Horde mentality into consideration and how it is affected by the heatmap. Zombies will eventually spawn somewhere nearby and start towards you. This will happen even if you don’t have any activity going on that creates heat events. Additionally, even the heatmap of that chunk will keep increasing over time.

Now, one possibility is that the whole zombie mechanism takes into consideration where you tend to spend most of your time. This could help with the zombie spawning. Now as the zombies continue spawning, approaching you and getting killed, this might lead to a compounding effect that progressively increases the heatmap. And if you use a lot of firearms, then that’ll boost up the heat even more. As a result, get ready for more zombie hordes!

Miscellaneous Actions That Affect Heatmap

Driving a minibike will add to the heat. Although this amount is not much noticeable by the zombies. Also, you’d probably been gone from the spot anyway! Another action that can increase heat is the opening and closing of doors. Remember we said above how metal objects affect the heatmap? It’s the same with metal doors and hatches. These increase the heat by 0.05 every time it is used. 

Activities That Don’t Affect the Heatmap

  • Your Bed does not contribute to the heat in any way.
  • While ‘running’ will create noise that might attract zombies, it does not create any heat events.
  • Fire of course creates heat. But, using light sources like a spotlight, that are not fire-based, will not generate heat.
  • Speakers don’t create any heat events. Although this might be a bug since speakers don’t attract zombies at all!

Powe sources like Solar Bank, Generator and Battery don’t affect the heatmap. Although it does create a very small and negligible amount of heat when you open them.

7 Days To Die Wiki Staff

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