Excavating Question

[Nazrex]

So I found a great POI in the northern edge of the desert, a nice Watch Tower with lots of resources around it, and close to both the Forest and Snowy areas, as well as a short drive to other locations... basically a pretty decent central location.

 

It got me curious about how it could have potential with some modifications.   So, first I cleared the ground under it then I started building a wall around it on the ground.  Once I got the wall up, and replaced the entry with a stronger Roll Up Door... I started excavation a 3x3 pit, straight down... which I covered with a 9x9 concrete block cap, and installed iron ladder pieces as I worked my way down... This pit is being excavated, directly under the watch tower itself.   

 

Encountering lots of iron, lead, sand and clay as I worked my way down, I used these various resources to upgrade and strengthen the wall, and eventually add a Roof over the Wall so that the Watch Tower itself was sitting atop this Roof... basically creating a Garage / Workshop directly under the Watch Tower. 

 

I kept the Watch Tower intact, even repairing some of its existing damage... though, as I added the roof over my work area, I replaced parts of the Watch Towers wood pillars with stronger blocks, so it had stronger support.

 

I then continued my excavations... working my way down until I reached a depth equivalent of about 5 Stories down.

 

My plan here was to eventually install the 9x9x26 Elevator.... which, I'm not sure if its part of the original game or part of the Undead Legacy Mod by Subquake... but regardless of that, it doesn't matter.   

 

What matters, is when I reached the proper depth with my 3x3 hole... I worked my way outwards until I had a floor space of 9x9 wood frame blocks.   The corners of this, marking the exact location of the support pillars above, for the Watch Tower.... and the location of where the 9x9x26 Elevator would eventually be installed.  

 

I planned to build a hardened bunker, 5 stories down, and use it as a primary base of operations from which could excavate outwards from to mine all the various lead, iron and oil shale that scattered around the immediate vacanty, and essentially mine all this stuff from underground, adding support beams as I worked to prevent collapses, etc... with the Watch Tower above providing excellent sniper opportunities during blood moons.

 

However.   Once I got down to that 5 story depth, and established the 9x9 corners... I started slowly excavation upwards above each corner and placing a wood frame block at each one, gradually building four pillars from the bottom, upwards... 

 

I got to about 3 blocks in height when I climbed back up to deal with a couple Screamers at my door, when I discovered... 

 

The Watch Tower had collapsed!!

 

Literally, just moments before this, just before I established the 9x9 corners at the bottom of my pit, it was fine. 

 

Everything else is also fine... the Garage/Workshop that I added, is fine... 

 

The Watch Tower's pillars and support beams are also still intact, just the structure at the very top seems to have been completely destroyed with debris all over the rood of my workshop, and scattered about on the ground around the outside.

 

So.

 

How did this happen?

 

Its really kind of a let down, cause I really liked the Watch Tower... I mean sure I could just go and rebuild it, eventually... but still... 

 

I just don't understand how it could have lost stability to collapse.

[Nazrex]

I have some screenshots of all this, for context.... but I have no idea how to post them, cause the button for "insert image from url" won't accept the urls from my Google Photos...

 

So I'll post these lightshot links instead...

 

http://prntscr.com/rxi1oh8kyhKh

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http://prntscr.com/yEDUpPwCYosM

http://prntscr.com/HyB1EMIdekOf

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http://prntscr.com/wwgJBMkJP3HD

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[RipClaw]

Structural integrity can be very counterintuitive in 7 Days to Die. In 7 Days to, a block has unlimited load-bearing capacity if it is vertically connected to the bedrock. When you excavated the 9x9 area, the tower on top of this area became unstable because it was no longer connected to the bedrock.

 

[Nazrex]

As it is right now... 

 

I kinda feel like I don't want to excavate down there anymore, and walk away from the whole project... least anything else collapses...

 

But then, I really just don't understand how the Watch Tower collapsed in the first place, and would like to know what I can do to prevent the rest of it from coming down... as the stairs remain intact, and the support pillars are intact so I could go up at some point, clear the debris and rubble and just build a new structure up there.

2 minutes ago, RipClaw said:

Structural integrity can be very counterintuitive in 7 Days to Die. In 7 Days to, a block has unlimited load-bearing capacity if it is vertically connected to the bedrock. When you excavated the 9x9 area, the tower on top of this area became unstable because it was no longer connected to the bedrock.

 

 Yea, this is the part that I don't much understand, as the bedrock was essentially still there... most of it above me.... so it was technically still standing atop something?

[RipClaw]

3 minutes ago, Nazrex said:

Yea, this is the part that I don't much understand, as the bedrock was essentially still there... most of it above me.... so it was technically still standing atop something?

No the bedrock is the indestructible area at the bottom of the map. It can never be above you.

If you dig straight down and can't get any further, you've reached the bedrock. You will hear a sound when you hit it that sounds like hitting something at the trader.

 

[Nazrex]

Ok, well I didnt go that far down... and once I established the 4 corners where the tower's main support pillars were located above, I only excavated 1 corner at a time, clearing 1 layer of material at a time and once it was cleared, I immediately placed a wood frame block... presuming that so long as the 4 main pillars maintained a solid connection all the way down it would be ok... 

 

I originally planned to gradually work my way back up from the bottom, 1 layer at a time, 1 corner at a time... until the 4 pillars were completed all the way down, and then I would upgrade them to better quality blocks... then install the Elevator within the original hole.

[Ramethzer0]

Yup.  Seen this before.   I learned that its never okay to mine below your base.   Always pick another spot.

[Nazrex]

6 minutes ago, Ramethzer0 said:

Yup.  Seen this before.   I learned that its never okay to mine below your base.   Always pick another spot.

 

So there's probably no way I could salvage/recover, from this, and rebuild the Tower?  Because the hole itself, that I excavated is the problem?  Just adding the pillars at the 4 corners as I work my way up, won't solve it?

 

Fortunately this is not my only Base... my wife and I play together and we still have our original base in the forest lands, we found a cool underground church, under an above ground church.. right next door to a Trader... and we set up there originally and gradually upgraded it... 

 

But I started this second base, hoping to surprise her with it.

[Syphon583]

Even before you posted the screenshots, I knew exactly what tower you were referring to. That one in particular is infamously unstable. But as others have said, in general you don't want to excavate a large area underneath any structure. It's almost impossible to predict what will happen on the surface, even with the well-intentioned idea of doing one corner at a time. If you were inclined to do this in the future, it's ok to dig a tunnel down, but afterwards dig a tunnel outward so that the none of the underground base portion is underneath the structural support of the building above.

 

To check stability in general, you can always enable DM in the console and then click the box for 'show stability' in the pause menu. It will color-code all of the building blocks to show how much integrity they have from green to red. You can try to shore up areas that look particularly weak.

[Nazrex]

Cool, thanks...

 

Its kinda discouraging, but maybe I can build something else there... 

[theFlu]

2 hours ago, Nazrex said:

Just adding the pillars at the 4 corners as I work my way up, won't solve it?

Technically you can build wonders just from a single central pillar. Not that I recommend it, walls tend to be heavy, a little like massive floating pieces of concrete would.

 

For a 9x9 footprint, you might get away with just corner pillars, but I would make more; a lot more if hordes are going to be involved. But at a minimum, one pillar at each corner, all the way to bedrock. But you don't need to dig to bedrock yourself; as long as no-one has been digging under the spot, the stone to bedrock is always solid all the way down.

 

If in doubt, steel connections offer a little more support sideways, but that takes a bit of thinking to take advantage of; a steel-stone connection is just as weak as a stone-stone one, so you'd need to upgrade extra blocks around your support pillar to increase the "carrying surface".

[Crater Creator]

There’s no guarantee that the structure was stable enough to remove even one pillar. Maybe it really did need all four pillars. I’m not sure if the timing matters, either. The game isn’t doing structural integrity calculations every frame (for performance), so maybe you can ‘pull a fast one’ by immediately replacing the destroyed block with a wooden frame, but I’m not sure.

 

Technically knocking out the pillars one at a time, while reducing the risk, isn’t ‘doing it right.’ You could have reinforced the support first, adding new pillars to take the load off the pillars (even pillars of dirt/stone) you want to replace.

 

It’s also possible that POI is inherently unstable. If you ever, say, destroy a painting on a wall and that causes a collapse, you know something’s wrong with the POI itself. Structural integrity isn’t calculated until a block changes, which is why inherent instability doesn’t show up right away. If you do see something like that, I would treat it as a bug worth reporting.

[Melange]

4 hours ago, Ramethzer0 said:

Yup.  Seen this before.   I learned that its never okay to mine below your base.   Always pick another spot.

Years ago I saw a YT by Games4Kicks, and he said in essence to never dig under your base because the physics gets weird and stuff will begin to fall. And he was right. Similar things have happened to me too, trying to push the limit while applying real-world logic. A rage quit did ensue (well I did abandon the project anyway). Bummer, and I share your grief. Rebuilding your tower may prove futile as well, but you can give it a try. Because something has been disturbed in the balance of things, and there's no way of telling what it is (apart from the dig in general). The game's physics calculations usually seem logical. But when it comes to burrowing under an existing POI, logic appears to be out the window. Lesson learned.

 

I am impressed with your build though. Hope you try it again in another way sometime.

[Syphon583]

14 minutes ago, Melange said:

A rage quit did ensue

Here we are talking about more rage quits 😆

 

I remember my very first playthrough of 7DTD. A19, Navezgane. I built my base in this very tower that the OP mentions. I was well into day 45+ (I honestly can't recall how far, but it was far). My horde base was at the base of this tower, but the way I had it setup was that the original supports would not be touched by zombies. I built a larger 3x3 central column that served as the horde base, and it extended all the way up to the tower itself. I figured with that central column, I'd be safe upgrading the original pillars to ensure it would remain standing in the event of errant demo explosions. Unfortunately at the time I did not know how fragile stability was in this game (definitely worse in A19). While upgrading one of the pillars (I had already successfully upgraded two of them) the structure decided it had enough and crumbled before my eyes. I don't know what triggered it, but the sight of my weeks of hard work, materials, supplies, food, weapons, everything crumbling to a pile of rubble was probably one of the saddest moments in my gaming life.

 

Lessons learned, of course. I don't think I've ever had a catastrophic collapse since, 600+ hours in.

[Ramethzer0]

6 hours ago, Nazrex said:

 

So there's probably no way I could salvage/recover, from this, and rebuild the Tower?

You can.  But, it requires a lot of work and materials, and you may not be happy with the final result.   It would involve digging up almost everything and replacing it bits at a time with solid blocks.  Essentially, it would loose its natural look and feel.  If that's not a problem, by all means.  You'd still need to stop all mining operations below it.

[Nazrex]

3 hours ago, Melange said:

I am impressed with your build though. Hope you try it again in another way sometime.

 

Oh I have lots of base ideas, and as frustrating as this incident has been, I dont want to give up on it.

 

The garage side of my structure... the side where the cars are parked, that side is solid and has solid ground under it.  I'm thinking I'll just knock down the rest of the Tower and then rebuild a new one on that side, so the excavated elevator shaft, is not directly under it, and I have no plans to excavate anything on that side.  The underground Bunker itself is going to be on the other side, closer to some oil shale and saltpeter deposits outside the structure, but very close to it.

 

Sure, it sucks that the original Tower is gone, it really did a lot for the aesthetic of the place.

52 minutes ago, Ramethzer0 said:

You can.  But, it requires a lot of work and materials, and you may not be happy with the final result.   It would involve digging up almost everything and replacing it bits at a time with solid blocks.  Essentially, it would loose its natural look and feel.  If that's not a problem, by all means.  You'd still need to stop all mining operations below it.

Yea and that natural look is what I liked about it.

 

I'll probably just knock down the rest of it, then rebuild a different one, but something similar, on the other side of the roof, so its situated over more solid ground under where I park the cars inside the garage... I have no plans to excavate under that spot.

[Laz Man]

Alot of those POIs with diagonal supports are very unstable, in that they cannot have a ton of stuff added on top of them without adding additional vertical support beams to compensate.

 

Most of those diagonal support beams are technically just for esthetics.

 

You can technically calculate how much mass each pillar type can support based on your support blocks mass and stability glue stats.

 

Here is more reference material as well.

 

https://7daystodie.fandom.com/wiki/Structural_Integrity

Edited August 10, 2022 by Laz Man (see edit history)