Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Celebrim42]

Hello.  First time earth striker here.  I've got a thriving Metropolis, but a real shortage of dwarf engineering experience.

I'm having trouble with the cave-in mechanics being unclear.   So I figured out pretty quickly that unlike minecraft there was an implied floor between z levels, that if you cut out the floor it collapses.  That's pretty intuitive although figuring out where you have a floor isn't easy.  I've also figured out that if you drop something heavy enough on the floor - say a tree -  it can crash down through it leaving a hole and sending debris into the area underneath.  I managed to figure out these things without losing very many dwarves, but I'd rather not lose more dwarves to trial and error, so I thought I'd ask a few questions.   

Right now accidental cave-ins are the leading cause of death (6, 2 of which involved knocking unconscious dwarves into water), followed by were-creatures (5, mostly by transmission of the curse), giant grizzly bears (1), and unexplained causes (1).   Cave-ins are much harder to deal with than any of the Titans and Forgotten Beasts I've had, which for the most part have been tremendous resources since they make huge stacks of tasty dwarf snacks and almost inexhaustible supplies of tallow.

First, how wide can you build a room before there is a chance the room collapses?  I've been care not to go more than 10 or 11 tiles without putting up a row of supports, but I can't really tell if this is necessary or me just assuming some level of reality that might not be there.  I've built up with supports to create watch towers, but I likewise don't know how wide a constructed floor can be between supports before there is a chance of collapse.

Secondly, I know walls provide some level of horizontal support, because when channeling you can leave piers of stone of some distance from the walls without a collapse (most of the time?).  But what is the limit to this horizontal support, and can you use it to support walls?  For example, if I have a place to stand, can I build a wall over a 'pit' provided that the wall is connected to an existing wall?  I know if I instead build a floor, I can't then build a wall on top of it.  It would be nice to be able to build a line of walls out across a pit or body of water to provide a non-retracting bridge as well as solid barrier, but if I'm wrong about that being stable the consequences would probably be pretty harsh.

Similarly, I know you can build walls on top of walls, but can you hang walls from walls?  According to the wiki, a 'Support' provides structural support both up and down, so I presume I can hang walls underneath a support, but can you also hang walls under walls?   Could you hang a support under a wall?   By the same logic, if I have a natural cavern column that goes up multiple z levels, if I tunnel out completely beneath it, will it normally stay hanging down (like a stalactite) or will the upper pillar (and possibly the roof) now collapse since it doesn't have either horizontal support or support from below?  Does the answer vary between natural walls, constructed walls, and supports? 

Thank you for any definitive answers.
 

[Loci]

Welcome to the forums!

First, how wide can you build a room before there is a chance the room collapses?

There is currently no limit. Even soil floors can span the entire embark without additional support.

Secondly, I know walls provide some level of horizontal support, because when channeling you can leave piers of stone of some distance from the walls without a collapse (most of the time?).  But what is the limit to this horizontal support, and can you use it to support walls?  For example, if I have a place to stand, can I build a wall over a 'pit' provided that the wall is connected to an existing wall? 

Any (supported) adjacent natural tile or construction provides sufficient support for building as many attached constructions as you wish. A single wall (or floor) tile can horizontally support your entire fortress. Nothing provides support diagonally, however.

Similarly, I know you can build walls on top of walls, but can you hang walls from walls?

Yes. Walls, supports, and stairs all provide vertical support, both up and down. Tiles with floors provide support to "vertical" tiles below the floor (e.g. walls hung below), but not above.

[Celebrim42]

Thanks.  I didn't think I'd get an answer so quickly.

There doesn't appear to be a way to up vote you, but again, thanks.

[PatrikLundell]

Structural support strength isn't modeled at all, so, as Loci said, the range and strength is infinite. You can place an enormous solid cube of stone resting on a wall made from a bar of ash (a lot of work of course, and a silly thing to do). If there is support, it's sufficient. And support is transitive, so if a tile has support, it will support the tiles above and orthogonally adjacent to it, and that will...

However, removing the last supporting tile will cause everything that formerly was supported to cave in. As you've noted, a cave-in will crash through floors until it hits a solid tile. A common cause for cave-ins is to order the channeling away of a floor over some cavity, and the dorfs will then channel away more or less randomly, usually resulting in cave-ins. You'd have to baby sit the removal to ensure tiles are removed in the correct order (i.e. never remove a tile before all tiles solely supported by that one has been removed.

Trees are a somewhat special case. Trees with a cavity underneath will result in a hole in the roof when cut down, so a recommendation is to avoid any building in the first soil level, and place the facilities in the second one instead. If you need something in the first soil level, remove the trees first and dig out the facilities afterwards, as no holes will form if it's done in that order. You may also want to remove all saplings on the roof e.g. building a single tile dirt road on top of each of them, as saplings otherwise can mature into trees that you chop down... New saplings will not appear on a roof (they need a soil tile for their eventual roots), but existing ones can mature. Note that cavern trees are somewhat different in that they don't have roots, but they still leave holes in the roof when cut down.

[schlake]

I managed to figure out these things without losing very many dwarves, but I'd rather not lose more dwarves to trial and error, so I thought I'd ask a few questions.   

The word is !!science!!, not "trial and error", and losing dwarves to it is exactly what you do.  You also lose dwarves when not doing !!science!!.  It's best not to lose sleep over lost dwarves.  More dwarves will come, but lost sleep is gone forever.

[Dunamisdeos]

I managed to figure out these things without losing very many dwarves, but I'd rather not lose more dwarves to trial and error, so I thought I'd ask a few questions.   

The word is !!science!!, not "trial and error", and losing dwarves to it is exactly what you do.  You also lose dwarves when not doing !!science!!.  It's best not to lose sleep over lost dwarves.  More dwarves will come, but lost sleep is gone forever.

You can, however, lose dwarves over lost sleep.

Also, a side note. Falling objects can and will punch through constructed walls and floors. I have had a single dwarven child fall and punch through 12 levels of solid masonry to land on a passerby and explode onto the walls. Natural ground/walls will resist damage from cave ins and falling objects.

Oh, and welcome! You'll find the community here one of the most active, friendly, thorough, and helpful places on the internet. No question is too silly, and no answer should be without some anecdotal story of violent horror if you ask me.

[Fleeting Frames]

That doesn't match my experience where floors get punched through but walls hold up to impact, though?

[PatrikLundell]

Constructing a wall under a (natural) floor worked to block a dwarf made cave-in (a floor on a support, to smash a Titan in the area below, but not make a hole in THAT floor). I think, however, there's a difference between dwarf made and natural stone/earth cave-ins as well.

[NullForceOmega]

When you cave in a constructed item it returns to its material state, so a boulder if you didn't make blocks, or blocks if you did.  Either way it has substantially less destructive power than caving in natural tiles.

[Quietust]

When you cave in a constructed item it returns to its material state, so a boulder if you didn't make blocks, or blocks if you did.  Either way it has substantially less destructive power than caving in natural tiles.

The tile which caused the cave-in is irrelevant - whether it was triggered by a natural floor, constructed floor, natural wall, or constructed wall, it will destroy all floor tiles (and creatures) beneath it until it encounters a wall tile (either natural or constructed), at which point it will stop.

The only way a cave-in can destroy a constructed wall is through a chain reaction, whereby the first cave-in causes the constructed wall to become unsupported.

[NullForceOmega]

I actually wasn't referring to the results of the cave in (breaking through floors) I was referring to its effect on creatures/objects.

[Quietust]

I actually wasn't referring to the results of the cave in (breaking through floors) I was referring to its effect on creatures/objects.

So was I - regardless of whether the caved-in tile is constructed or natural (or floor or wall), it is instantly lethal to everything directly beneath it. Caved-in constructions are arguably more dangerous, because the building component can fall down afterwards and cause additional damage to anybody who is moved underneath by the dust cloud.

[NullForceOmega]

I actually did not know that, my understanding had been that collapsed constructions immediately deconstructed back to their constituent item, and would thus be less dangerous, thank you for clarifying that for me.

[Halnoth]

collapsed constructions immediately deconstructed back to their constituent item

Yup they do. Sorta like how when a recking ball slams into a brick wall, the brick wall is of course immediately deconstructed back to its constituet items. Of course in the process bricks fly everywhere but hey the statement is accurate nonetheless.

[Dunamisdeos]

Consider me educated.