CustomNPCs can't see a target through a top half slab, but can see a target through a bottom half slab.

[RagexPrince683]

[RagexPrince683]

Also just a suggestion but maybe making cnpcs see through leaves and or their projectiles go through leaves would be a good addition.

[KAMKEEL]

@RagexPrince683 I don't think most mobs can see through a top slab can they?

[RagexPrince683]

Not sure about most mobs—do custom NPCs count as vanilla mobs in that case?

[KAMKEEL]

Well they're modded mobs @RagexPrince683 but, it has to do with their Eye Height