Confusion about luminosity and mob spawning.

[Daemon_Eleuel]

Ok, I am playing and I keep getting creepers spawn in my base.

I did set glowstone illuminators always on on the ceiling, one every 3 meters, but I still keep getting spawns.

Are illuminators not a valid light source to prevent monster spawns? :|

[Magicthize]

They should be. If they're high ceilings they might not actually be illuminating as much as you think. F7 is your friend. It'll toggle an overlay to shows areas that mobs can spawn.

[Daemon_Eleuel]

Ah, very helpful information, couldn't find that anywhere, sorry if it's a redundant question :|

[funknapkin]

Remember to turn on the illuminators. They're off by default, you can switch their mode by right-clicking them with a valid buildcraft wrench. I prefer the 'always-on' mode for lighting my base, which you get by wrenching an illuminator 5 times.

Also, lights can only go so far. If your ceiling is too high, the light won't actually get to the ground. Press F7 to see the areas mobs can spawn.

[Dewfire]

Floodlights are handy for high ceilings. I was not aware of F7, all this time playing!

[jakalth]

It also only takes one slightly darker corner for a mob to be able to spawn. Nice part is, they can only spawn if the dark spot is below them, on the floor. It does not matter how dark the ceiling may be.

Ceiling lighting only matters for aesthetic reasons. As in, it looks nicer.

[TokiWartooth]

Omg i didn't even know about f7 ive been using F3 and looking at the raw light values checking each square fml.