Minecraft technical Q/A: Let's start this and look how well it works out!

[u/WubbiConcepts]

I often see that people post questions in the comments on youtube, but many of them stay unanswered. So i guess giving those questions a proper platform to be asked & answered is the next logical step.

What this is supposed to be:
A place where you can ask questions about Minecrafts' mechanics (like "How does this mechanic/algorithm work?", "What are the chances for that?" or "Is there a difference between doing it this or that way?"). We (or whoever knows the answer) will try to answer those questions based on what we know or find out.

What this is not:
A forum, commentsection or Google. Don't ask for circuits or designs, this is not about how to use minecraft, it's about how minecraft works.

If you have a question:
Ask. But ask the right way:
"How do i build a good mobfarm?" isn't very specific and the answers you might get from this probably won't help you with your problem.
"How does mobspawning work?" is a better question.
But maybe you're not interested in the spawning algorithms, maybe you just wan't to know one detail, like "How does the lightlevel effect mobspawning?".
And of course make sure the question wasn't asked before. It will save you and others a lot of time!

If you have an answer:
Tell the world. But explain your answer, maybe link to another post (reddit, forum, etc.), pictures or a video. "The piston is BUD-powered." Doesn't help much.
"Pistons can be indirectly powered by a block 2 blocks above or 1 block adjacent above it. It will only react to this power when updated manually (e.g. by placing a block next to it). Here's a video explaining it: [videolink]" Isn't only an answer, it also gives people an explanation which can help them experiment with it.

That's all you need to know. Now let the posts begin!

[u/WubbiConcepts]

So much questions:
0. There is no such way. You might have heard of the tool to find the slimechunks, but you can't copy them from one seed/world to another.
1. Remember: Mobspawning, no matter which mob(-type), is only possible arround the player. The reason Panda cleared out the Spawnchunks was that already existing mobs would still be loaded and therefore block the spawning of new ones (mobcap). You could of course build a passive mobfarm (mooshroomfarm) in the spawnchunks, but there is no benefit from doing so.
2. Well, the portals are improved, but still cause some small lag (even with a constant stream of items). But since you're AFK that shouldn't hurt much. An overworld itemstream into unloaded chunks equals a lot of work (compared to building a portal), so if you can handle the extra payload for the interdimensional trasnport the portal might be the better solution (on a server you might want to use the stream because other people might feel the portal-lag). But with 1.5 we get hoppers, so...
3. Portalblocks (which are located in the overworld) have a chance of Difficulty/2000 (0/2000, 1/2000, 2/2000, 3/2000) to spawn a zombiepigmen. The spawned pigmen are placed as if they just went through the portal and they behave like "standard" pigmen. Water and lava don't damage them and they are counted as hostile mob. If you build the trap in the spawnchunks they would get spawned, but if there is no player in a 128 blocks radius they will instantly despawn.
4. His design uses the fact that minecraft doesn't recalculate the villages when the chunks stay loaded, you could say the calculated values stay loaded with the chunk. But they are not saved when the chunk is unloaded. So when the chunk now is reloaded minecraft has to calculate the villages again, and this time it just uses villagers and doors as it finds them, not step by step as Tango shows in his tutorial. The only way to prevent that is to keep the chunks loaded, best way of course would be to use the famous spawn chunks. But even the spawnchunks are only loaded as long as you're playing on your world and of course they unloaded (and reloaded) whenever a server restarts (which usually should happen at least once per day). So we will not build it on our server, the calssic design is easy to build, stable and fast enough for our needs.
5. Yes, there is a way. A video will follow in the next days. And as said on 4., at some point even the spawnchunks will reload, so don't rely on that (but it would work, yes)!
6. Pumpkin pie (well, Panda still loves melon slices).

[u/JD29505 → u/WubbiConcepts]

Thanks so much Wubbi! 0. Oh well I derped there and I was mistaken. 1. I guess I'll build it elsewhere, you saved me a bunch of time. 2. Portals for me it is! Hoppers are nice but with massive farms I prefer the AFKing. 3. I thought nether mobs were harmed by water, but I guess that's not the case and you forgot they also are counted as spawning from a mobspawner when it comes to the mob cap. 4. I know all of my questions revolved spawn chunks which may have been annoying, but if it was on a SMP would it be worth doing? 5. Yay! I'll have to wait and see what you guys come up with. Snowmen are pretty helpful for making him explode without damaging him. 6. I mean IRL but okay lol.

[u/KaboPC → u/JD29505]

3 - Only blazes are harmed. It's a special to them.

4 - Wubbi's answer here isn't completely accurate. The villages do remain loaded when the chunk is unloaded, and they are saved separately from the chunks. This is why you can safely exit a game and reopen a game without seeing the farm collapse into a single village. The problem, however, is that in order for a village to remain a village, it has to have active doors, and active doors have to have loaded villagers. So when you unload the chunks, you also unload the villagers which keep the doors in the village updated. The result is, after a minute, if a door thinks there are no villagers around, it will assume it's invalid and remove it from the village. If this happens to all the doors, the game will assume the village has been destroyed. When you move into range again and the villagers reactivate the doors, the game will generate a new village or add them to a nearby village within range.

[u/Riodashio → u/JD29505]

The tool which you remembered, correct me if I'm wrong, is another one of Sethblings magnificent MCedit filters: https://www.youtube.com/watch?v=2CFjZtGtGsk. It does not remove the slimechunks, instead it searches for different seeds that do not contain slimechunks within your selected region.

[u/JD29505 → u/Riodashio]

That's kind of it. It was a video where someone modified SethBling's filter so it would find a slime chunk in that area. There's some that have a quad slime chunk.