main building structure box is inconsistant, i can build assembly machines "inside of it by one tile from the bottom of it. its area also isnt very defined when building around it and the top bit covers a large amount of buildable space, hiding it. Should probably think of something else as the "heart" maybe something like the shelter from Krastorio2 or a silo like structure that is more underground?
Ill see what i can do about it, probably there's some free textures or building sprites that i could use, im new to modding, ill do my best for the next patch!