Like dwarven engineers digging deep into the heart of a mountain, we are going to dig a huge cavern and cuase it to cave in , leaving us with many layer deep silo to build out base in.
So as you probably know stability is based on the distance from a stable structure – starting with stability 4 and decreases 1 for each voxel distant from that structure.
So you can a cave in by digging a room 7 by 7 wide, and the central voxel will collapse. Not only this but it will collapse ALL voxels above it!
We can use this principle to dig out deep silos, first you dig a long tunnel into the mountain, and try to get as deep as you can (or need to). If you choose a tall mountain you can excavate 8 or more levels. For my game i started excavation on level 6, and the mountain went upto to level 13, so my silo was 7 levels deep.
Once you have dug you tunnel to the area you want your base you begin to excavate the
Decide the shape of the silo you want to build, we will cause a cave in that excavates that shape from the bottom layer all the way to the top.
Since it take time to dig into Lime Stone, the most efficient size is to create a 10 voxel long room , as this is the maximum distance supported by wooden beams that will support the ceiling, the room can be as wide as you want so long as you continue to add support beams.
I chose a 7 by 9 shape as I like my rooms to be symmetrical about the central line. You then need to excavate this shape plus 3 additional voxels in each dimension
So for the 7 by 9 room , you will dig a shape roughly 13 by 15 voxels accross
The grey area is the excavation or basement.
The white ares is the cave in area.
The cave in will happen progressively as you continue your excavation, i find it helpful to use a Stockpile (set for Limestone) to mark out the cave in area. Then you can count 3 squares from the stockpile to determine the area you need to dig.
Once you have got the hang of it you can create more complicated shapes. I usually add a 3 by 3 area at the end to put the stair case in. I also add alcove to the main room to slot in some big workstations.
The blue square are walls to create a space for a door way.
its time consuming to dig at first, but it saves allot of time in the long run. the bonus is you also produce ALLOT of Limestone if you dig into a mountain.
Note: the excavation will destroy anything above it, like gold or iron seams.