When digging out a cave you need to FIRST place the door then dig through behind it.
If you first dig out the cave and then want to have a door (Large Door is the one that fits) then you can’t place it in the opening because the door is anchored to the center of the tile on the wall, not on the ground or inside the cave walls.
It would be nice if the doors matched the size of the diggable entrances. So if you dig a one-wide channel it will fit one ordinary door. If you dig two channel wide it will fit a double door.
Also it seems that the doors height is off by one Voxel for this to work.
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