how did I turn on this weird block overlay?

[BabaTheFool]

I was opening the door to my kiln and all of the sudden this red,yellow,green overlay covers it. How did I do this, whats it for, and how do I turn it off?

[Brady_The]

10 hours ago, BabaTheFool said:

How did I do this, whats it for, and how do I turn it off?

I do believe that this is the build outline for the cementation furnace. You activate it by Shift + Right Click and deactivate it by Right Clicking the stone coffin.

[C_Man]

It is the overlay for building a cementation furnace for steel processing indeed, but why did you build yours out of stone bricks? They need to be built out of refractory bricks to work. It can be activated by holding shift and then pressing right click on the stone coffin, and deactivated by just clicking on the stone coffin again. Second thing: If this is a structure for kilns and not built for steel processing, why do you even have a stone coffin in it?

[BabaTheFool]

OOOOoooooh, I wasnt making a steel structure I was just making something to make charcoal above ground lol

[C_Man]

Then you won't need the stone coffin. Chuck it outta there and throw those piles of wood in!

[Forks]

1 hour ago, C_Man said:

Then you won't need the stone coffin. Chuck it outta there and throw those piles of wood in!

I believe the overlay can also be activated by shift+clicking on the refractory door, we use one for our cellar and misclick when sprinting in all the time.
So they may not have a coffin at all in there.

[C_Man]

Ah, yes, that's a newer feature I forgot existed. The door shows the overlay for the beehive kiln which was added in 1.20. Then @BabaTheFool will have to do the same actions on the door as on the stone coffin to show or hide the overlay. Thanks for the correction @Forks!