Height Map and Pack Spawning Crash Course for Minecraft

Hello ladies and gentlemen just wanted to make a quick video today to answer some questions uh that we’re just going to cover the basics of the height map and mob spawning so let’s get into it So i just want to make a brief video if you want a lot more details on this subject check out the uh videos by methods and logical geekboy on dissecting minecraft or nem bombs videos on his fun farm series specifically the enderman farm one they talk about this subject a lot

More in depth this is just going to be to kind of explain the basics because when i learned this it completely changed the way that i thought about mob spawning in front of me here i have a representation of four chunks in minecraft what they look like going all the way down to

Bedrock all the way up to the top and what i want to talk about is first the height map what the height map is it is the top block in a x and z coordinate so going this way and going this way the top block in that coordinate makes up that height map

So for this chunk right here this would be what the height map is like so this height map here is representing these four chunks right here and we can see so that would be the top of each block now notice i’m saying block but it’s not just necessarily what you

Think of as just a grass block here right here we see we have flat with a couple of flowers over here we have not flat because those flowers this grass all that stuff is included in that height map so any non-air block in a block brings the height map all the way up

From negative 64 or zero in the other dimensions all the way up to where this block is in that x and z coordinate we can see over here i have this nether portal right here and right over here underneath it we don’t have any of the height map there it goes all

The way to the top of this portal so that is the height map so if a specific x and z is chosen for a spawning attempt then it can go all the way up to the top block in this scenario so when the game gets to the part of the

Tick where it’s going to spawn mobs it first picks a random x and z coordinate so it picks that random x and z where those intersect is the column that is chosen for spawning and then it’s going to choose a random y value inside that column that is chosen at that

Intersection the y value is going to be between the bottom of the world so in the overall negative 64 and the top of the height map for that column so in this case 71. so that’s 135 blocks so that means if we want to get a mob to

Spawn on this spot right here we have a 1 in 136 chance to get that mob spawning here when this column is chosen for the spawn attempt one of the other things that doesn’t really change mechanics but is interesting to know is in each tick that spawn attempt still

Happens so let’s say that this block is the one that’s chosen and this is air i’m just representing it with this red glass this would fail because a mob can’t spawn in air however the game is still going to attempt a spawn there so just because it’s air or it’s covered

With glass or it has pressure plates or buttons on it that doesn’t mean the game can’t try and spawn on it the game will just constantly try and spawn everywhere and only if that place is spawnable will then a successful spawn attempt take place this is why you see a lot of people

Saying online when they make recommendations about building farms to build them as low as possible in the world so here if i have a spawning platform at y level 60 uh sorry negative 60 so maybe for like a slime chunk that you dug out or something like that this now

Has a one in five chance of this being successfully chosen because there is nothing but air above it now that doesn’t necessarily mean that building lower in the world is automatically good it needs to have that height map removed in order for it to take effect so if i build that spawning

Platform right there but i still have blocks above it on the hype map that block down there that spawning platform is now still a one in 136 chance so just by having these blocks up here you’ve raised that height map all the way up and greatly reduced the

Chances of getting a spawn attempt over here i’m going to show that where we have a spawning platform down at negative 64. so if i come up here and time set midnight you can see how fast those mobs actually start spawning because now that it’s at

Negative 64 there’s a one in two chance that that block will get picked for a spawn attempt so we are already at mob cap with this whereas if i come over to here where i have a spawning platform at y 0 so from 0 to negative 64 it has a 1 in

65 chance of spawning you can see how much longer this is going to take to actually fill up two spots two spawns so that’s why you see it representing as uh you want to build it as low in the world as possible when you find advice online now

If i take that same spawning platform down at y negative 64. and i add blocks above it so even though we still have all full air up there you can see how long this is going to take to actually fill in so we’re now getting those same kind of spawn rates

Except for the bats as we are on that other platform so we’ve affected that height map so we’re still getting some spawns here because it’s an open spawning platform but that’s significantly slower than before so if you are going to clear out chunks for some kind of farm down there and

It’s going to involve mob spawning you want to make sure that you also clear out the height map as well so every block in that column that raises the height map which again is every non-air block and this would also apply to the nether too even if i cleared out a bunch of

Chunks of the nether all the way down to y uh zero and i just had a spawning platform there because i have the bedrock ceiling above me that still raises the height map all the way up to 127. so this is still a 100 a 1 in 128 chance

To get picked for that spawn so the only way to bring that hype map all the way down is to get that bedrock removed so that over your spawning area and your spawning skirt you have all the way down to where you want it to start now i mentioned the term spawning skirt

And that’s another thing that i want to cover on here is uh mob pack spawning and that also deals with our height map as well you may notice here this layer of dirt was significantly larger than our little platform down there and that’s because down at this level even if i was to

Leave some blocks up there because i have it all clear out here i’m going to get pac spawns coming into my spawning platform so we have a platform of dirt here and let’s say that this block right here gets picked for a spawn attempt of a zombie

This right now would fail because it’s daytime but if this had a correct block light this would succeed it’s a spawnable block there and so a zombie would spawn there the game is not done there once it starts its spawn attempt on the zombie whether or not this fails so

Let’s say this block here was the spawn attempt it fails it’s now going to continue its pax pointing attempts and what that is is the game will then move five blocks in a random direction so one two three four five doesn’t have to be in a straight line it could be one two

Three four five so it can loop around like that and then it’s going to see if it’s a valid spawn attempt and in this case say nope not a valid spawn attempt most mobs in the game have a pack size of four so this still has two more times

To go so i’m gonna say one two three or five in this instance if this was the correct block light this would be a successful song and then it does its next one two three say four or five and this one would be successful so even though the spawn attempts started here

We still have a chance of getting two zombies out of that spawn that could be zombies skeletons almost all the mobs in the game have a pack spawning so these pack spawns your max possible efficiency to have that skirt is going to be 20 blocks out because each time it

Attempts that spawn what it’s going to do is it’s going to pick a number between 1 and 5 randomly on the x and then randomly on the z and then it’s going to move in that direction so you know i was showing it earlier with it kind of snaking over like this it

Doesn’t actually do that when it picks it so it’s going to pick let’s say it picks three and then it picks two so it would be there so it’s going to move in those random directions so you theoretically can have a chance of a failed attempt starting here

And then it picking five and five so uh one two three four five and then one two three four five here i have another failed attempt there and then one two three four five one two three four five there there and then you could have one spawn right there

So i’ll show you here and the one where we have the area of dirt above it if i fill that area of air back in with glass so that we have some attemptable spawnable blocks there with the height map being raised up with that piece of glass

We can see that we’re getting mobs a little bit faster and you’ll notice they’re on the edges there because they’re actually coming in as pack spawns in this these instances that’s why you’ll see these skirts of some kind of spawn proofed blocks so here we have pressure plates here we

Have stone slabs here’s trapdoors glass we can have spawn attempts start out here maybe it wanders over here wander’s over here and then we get one in there in this case we only got one sometimes you’re actually getting you know so we get a failed attempt here but then successful successful successful so

We’re getting three out of that but you’re still getting an increase of rates it’s not going to you know double triple anything like that but you’re still going to see an increase in rates because those spawn attempts can start on the skirt and get pulled uh we have

Pulled i guess isn’t the right word wander into your spawning platform the reason that is is because this skirt that’s sticking out now raises the height map of all this area so over here you can’t have any spawn attempts wandering into your spawn platform because the height map here is down at

Negative 64. whereas here on the side the height map has been raised over here all the way up to zero so now it’s on the same level there again you’re not doubling or tripling any rates with this but you’re raising the surrounding height map you also only need to put that pack

Spawning skirt at the very top layer of your farm because if you have even if you have a bunch of spawning platforms down here out here this hype map is still raised up to this level right here another thing to note in this instance i actually have set up here this is

Actually bad because right here this pressure plate is one y level above this so that’s actually going to add one more what you actually want to have is you want to have that at your top spawning layer exactly so in this case would actually want to have it like

That because it’s going to attempt to spawn on top of this pressure plate as well so the same y level as our spawning platform so hopefully that helps you out um hopefully that answers questions you had if it raises more questions then by all means continue to check out again that

Dissecting minecraft series with logical geekboy and methods that’s a great resource uh they have a couple videos i think it’s episodes 10 and 11 if i remember correctly check out the enderman farm episodes by nem bomb and uh then be sure to ask around on the tech community if you’re if you’re not

Sure about something we’d love to answer your questions i feel like this is one of those things in mob spawning that really gets ignored when it gets explained because it seems like it’s a difficult concept but really think of it as just picking a random x and z

Where those intersect picking the top block in that column and then picking a random location in between the bottom of the world and that top block and then starting spawn attempts so let me know down in the comments if you have any more questions check me out

On twitch and i hope to see you later have a good one bye You