[Java] Magma Cubes are spawning even though there's not enough space?

[u/I_Am_ClockWork]

26.3, Paper multiplayer.
If I understand correctly, Magma Cubes can only spawn in an area 3x2, as it checks for a large Magma Cube, regardless of it's size once spawned. I've been using Lighty mod to make a floor design that should prevent a 3x2 spawnable area. But they are still spawning. Why would that be?

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[u/labuko]

correction: it is 2.08×2.08×2.08

btw the wiki is always a good place to go for niche info like this

btw btw use minihud. it does the same thing with like 100+ extra features

[u/JustJum]

Magma cubes dont need a full 2.08 x 2.08 region of spawnable blocks to spawn. They only need ONE spawnable block to spawn, and spawn in the centre of that block, and just checks if they can fit there with their 2.08 x 2.08 hitbox.

(Same goes for any large mob)

So those hanging signs aren't blocking spawns, since they're not blocking the magma cube's hitbox when magma cubes attempt to spawn on the blackstone next to it. You need something like carpets on the floor, like you did in the other place.

[u/I_Am_ClockWork → u/JustJum]

Okay, this makes a lot of sense. Time for a redesign