I have noticed inconsistencies with mob spawning at certain Y-values (higher altitudes).
I will explain how I noticed it - I started to build a simple dark room mob trap - the "collection area" was at y-190 above an ocean biome - I then stacked up 23 blocks and built a simple mob trap.
Once the spawning pads were done and it was fully dark I climbed back down...
What did I expect to happen? The mob spawner to be dropping mobs like mad - the only spawnable space close to me was in that constructed mob trap.
What actually happened: Nothing - no mobs spawned. I relogged several times - checked the spawning pads for light but no mobs would spawn.
I know that mobs become idle at a certain radius but I built it well within that radius.
I also know that no mobs spawn at 240 and above but again the spawning pads were not built anywhere close to that.
Also the spawning pads were 24 blocks away from me - It wasn't a case of me being too close
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Okay so I built another grinder - this time I built the collection area at Y-160 with a 24 block drop above (at about 184) to kill the mobs - what's weird is that I will get about 8 mobs falling and then after that it just stops.... I have tested this in both singleplayer and multiplayer (with only me on the server) and same results...
I guess the most frustrating thing about it is that I spent so long building and designing the trap just to see no spawns - I will include a picture of the mob trap above
This is the mob spawner - as you can see I am y-160 - the mob trap is at around 184 - there are no mobs spawning.
Hi I'm having the same issue.
I have a mob trap starting at Y=95, all caves around have been lit so its the only possible spawning space.
When I enter the game some mobs spawn but after that it almost stops, only 1 or 2 mobs spawn if I'm lucky.
Using Rei minimap I can see that there are no mobs anywhere else.
However if I move near chunks that have unlit caves monsters start to spawn on those chunks.
I've had this trap since 1.2.4 and until the last update it worked fine.
Ok I found a solution.
Acording to this thread "mob spawn rates are tied into the number of chunks loaded in memory"
http://www.minecraftforum.net/topic/1551224-mob-spawn-fairly-much-non-existant-on-survival-142-server/
So just increase your render distance and/or view distance (if server) and mobs will start to flow down =P
Not sure this is intended though.
Wow thanks for the share! 😛 - this actually fixed it - how strange, this can't be intentional though
Also, you can build some "antennas". If you place a few blocks above your trap, you'll keep that chunks loaded and the trap will work.
Yes I did initially try the antenna trick at first but that doesn't seem to work anymore - in fact a lot of people have commented on that video that the antenna no longer works - I suspect 1.4 had something to do with it
Oh yeah? I'll need to revisit my sky trap then, but looked like it was working full power.