40d Talk:Cave-in

Is this still valid? I recall that only truly disconnected areas cave in these days...

Yeah, this is what I've heard. I'm digging out a bunch of greater than 7x7 rooms now so we'll find out shortly. --Karlito 00:26, 30 October 2007 (EDT)

I've dug out some big rooms (10x10 I think is the biggest so far) and not had a cave-in for a season or so. I'm thinking it only does it on disconnects. makes it ALOT easier to plan your fort out. --BurnedToast 00:33, 30 October 2007 (EDT)

No kidding. What are the chances of accidentally completely disconnecting an area? I think that Toady One is going to continue to tweak the cave-in circumstances, though, so some things that don't cave in now may in later versions. --Peristarkawan 12:56, 30 October 2007 (EDT)

Sorry, but I don't understand what a disconnected area is. Could you try to explain? sinoth 12:50, 30 October 2007 (EDT)

A disconnected section doesn't connect to the rest of the map. As far as I know, that means it checks above, below, north, south, east, and west of a block of stone for connecting blocks, and continues checking through them to make sure the section isn't isolated. Toady mentioned something along the lines of it only checking for disconnects around the area you are mining. If the section is isolated, each block of the disconnected section will fall straight down. That's the general idea, I believe, and such disconnects are not easy to create. --Janus 13:12, 30 October 2007 (EDT)

I can easily see how to create an isolated support, but how would you create an isolated room? The dwarves would have to get there somehow... Also, wouldn't an isolated room (with nothing on any side of it, including above) be less likely to collapse because there's nothing nearby to collapse into it? --Bobson 13:49, 30 October 2007 (EDT)

1. Build a box with constructed walls from the ground.

2. Remove the construction connecting it to the ground.

Also, an isolated room, would have to collapse, unless we've got anti-gravity-field-generators. --Savok 14:59, 2 November 2007 (EDT)

I've mined out several levels underground. Then I dug channels (carefully) around the edge of the top layer. Once the last channel section was finished... bam! Cave-in. Only, it didn't stop at the first level below. It kept going to the last level dug out, taking with it all the loose debris. If there are any BUILDINGS in the region that collapsed, they will break apart. --AzureLightning 14:04, 30 October 2007 (EDT)

"Don't pay any attention to the information below this line! It is simply a placeholder!" - Why have it there if doesnt need to be? Take it away and re-add when something worthwhile is to be said. --Mizipzor 17:51, 31 October 2007 (EDT)

When building my underground farms with light access I had a lot of collapses but once the room was finished they ceased. There 8 by 8 and three floors down with open air access. I think a collapse happens if you have a room greater the 7x7 horizontally and more than 3 vertically. From what I've observed it seems like it only checks for a collapse every time a square is dug. --Lucid 20:57, 31 October 2007 (EDT)

I dug an open pit in a sandy grassland region. The pit was 4x6 and one level below the surface. And yet, somehow I had a cave-in. It was minor, and only knocked my miner out for a few ticks, but I'm still trying to figure out why an open-air pit would register a cave-in. (In addition, nothing actually changed as far as the pit topography.) --RedKing 01:58, 4 November 2007 (EDT)

If you dig all the way around the edge then that causes a cave in, i.e if you make a C shape and then dig out the remaining wall the center will fall down. This will destroy any buildings underneath.Jikor

Avoiding

I removed the 7x7 info until someone can verify that it's relevant in the new version. I'd also be interested to know when rockslides or shearing happens. --Turgid Bolk 16:44, 13 November 2007 (EST)

I can confirm that the 7x7 thing ISN'T valid as of 39e. I've had a 10x20 room with two solid layers on top of it for years and it hasn't collapsed. Only three walls, too. --CrazyEyes 11:00, 06 August 2008 (PST)

Cave-Ins In and ice...

Cave ins aren't supposed to damage the floor below? Is this still valid? I found an occasion where they do.

As sometimes happens, one pond froze over on my map. I dug down under the ice, and removed the support from under an island in the centre of the pond. I also dug a room (crypt) under the pond.

When the ice melted come spring, the 'ground' on the surface of the pond lasted a few seconds before realising it should collapse, and when it DID collapse it punched a hole into the room BELOW the pond. I know the hole was punched there becase next winter the ice froze down to the room below ONLY in the tils right below where the cave in occured, the rest staying distinctly wet.

Cave-ins and Ramps

I was under the impression that ramping the floor will dodge any cave in or isolation concerns that occur with channels, however, this is not the case, if a tile has water on it and is the last of adjacent tiles to be ramped there will be a cave-in. Is this due to water having weight and a feature or a bug? --Stalinbulldog 11:56, 9 September 2008 (EDT)

Confirmed

"Any item caught under falling natural terrain is encased in stone and must be dug out destroyed completely." I saw this has a "Verify" next to it. I have a video that confirmed it(started a hermit challenge). Here is the link ->http://mkv25.net/dfma/movie-1001#lastComment --0todd0 01:04, 23 December 2008 (EST)

I honestly don't see how this verifies the statement. --Edward 00:31, 24 December 2008 (EST)

I've verified that falling floor tiles will cause damage to whatever they hit but they don't destroy items. Falling walls will completely obliterate anything beneath them, with the exception of constructed walls which work like floor tiles. I've also noticed dust pushes items as well as units. Note that I'm using version 40d9. --Xonara 00:54, 24 January 2009 (EST)

Cave-in vs. objects

I'm pretty damn sure I've destroyed a unit of fire imp fat using a dropped (and constructed, no less) floor tile. 40d, too. --GreyMaria 19:21, 24 January 2009 (EST)

IIRC the movie above shows some bituminous coal surviving some falling floor. I tested it with some kind of yellow stone and a mechanism and it didn't seem to destroy anything, just pushed the stuff around. Are you sure it didn't get pushed off a cliff or into some magma or something? I don't know :/ --Xonara 04:32, 25 January 2009 (EST)

It was nowhere near magma or cliff. --GreyMaria 12:37, 31 January 2009 (EST)

Cave-in vs. creatures

I have had many instances where my dwarf stands underneath a section of semi-support cave connected to the ceiling above him, and then survive mining out the supporting wall and have the ceiling fall on him. He was superdwarvenly tough, but this seems to contradict "Any creature caught under the falling material is crushed and killed." --FJH 13:24, 8 March 2009