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[expwnent]

So no bridge elevators then? Darn.

[Kaos]

When I tried flinging rocks by raising a one tile drawbridge all the rocks vanished instead of being flung.

Yeah. People don't mention this much, but the "wall" tiles of a drawbridge crush things when the bridge raises just as surely as the other tiles crush things when the bridge lowers.

I've noticed this too, I created a 1 tile long rise bridge hoping it won't atomsmash things since the tiles where it lands were the same as where it was linked to and where the wall will be created... to my surprise it did atomsmash...


I'm not sure if it atomsmashes when lowered or rised though...


Mine were a 1 tile long 3 tiles wide rise bridge closing the entrance to a 3 tiles wide corridor, notice that the tiles on top of the bridge were covered with floor tiles, so the bridge was "inside"....


I think it atomsmashed things when raising too by crushing them to the ceiling... I theorize that if the ceiling is open space it won't atomsmash and only throw things...

[Sphalerite]

I've noticed this too, I created a 1 tile long rise bridge hoping it won't atomsmash things since the tiles where it lands were the same as where it was linked to and where the wall will be created... to my surprise it did atomsmash...

I'm not sure if it atomsmashes when lowered or rised though...

Mine were a 1 tile long 3 tiles wide rise bridge closing the entrance to a 3 tiles wide corridor, notice that the tiles on top of the bridge were covered with floor tiles, so the bridge was "inside"....

I think it atomsmashed things when raising too by crushing them to the ceiling... I theorize that if the ceiling is open space it won't atomsmash and only throw things...

A single tile long raising drawbridge will turn into a wall when raised.  Anything which is standing on it when it is raised will be atomsmashed.  It does not matter if the drawbridge has a roof over it.  If there is no roof on top of it, objects dumped from above onto an already-drawbridge will simply sit on top of it one Z-level above it.  Lowering the drawbridge at this point will simply cause the items to fall onto the now lowered drawbridge, and no atomsmashing will occur during the lowering.  Single tile long drawbridges can't fling anything.

[Kaos]

I've noticed this too, I created a 1 tile long rise bridge hoping it won't atomsmash things since the tiles where it lands were the same as where it was linked to and where the wall will be created... to my surprise it did atomsmash...

I'm not sure if it atomsmashes when lowered or rised though...

Mine were a 1 tile long 3 tiles wide rise bridge closing the entrance to a 3 tiles wide corridor, notice that the tiles on top of the bridge were covered with floor tiles, so the bridge was "inside"....

I think it atomsmashed things when raising too by crushing them to the ceiling... I theorize that if the ceiling is open space it won't atomsmash and only throw things...

A single tile long raising drawbridge will turn into a wall when raised.  Anything which is standing on it when it is raised will be atomsmashed.  It does not matter if the drawbridge has a roof over it.  If there is no roof on top of it, objects dumped from above onto an already-drawbridge will simply sit on top of it one Z-level above it.  Lowering the drawbridge at this point will simply cause the items to fall onto the now lowered drawbridge, and no atomsmashing will occur during the lowering.  Single tile long drawbridges can't fling anything.

So there is no way to have a raisable wall (a drawbridge) sealing an entrance but without the atomsmashing?


Now that you mention it, that was what happened to me, when a goblin was on the lowered rise-bridge and it was raised it would get atomsmashed, i was wondering if the ceiling had anything to do with it...


What about the opposite?, a creature or thing is standing next to the wall created by the rise-bridge when it falls down does it get atomsmashed too? pushed? anything? my observations indicate that no, but I could be wrong since I wasn't in a controlled experiment when I noticed the behaviour...

Another myth about draw-bridges is that when raised the wall has a weak side (inner) and a strong side (outter), building-destroyer-wise... I haven't tested this myself but it's something I've read in the forums...

[Sphalerite]

So there is no way to have a raisable wall (a drawbridge) sealing an entrance but without the atomsmashing?

That would be done with doors or floodgates.  Of course, those can be destroyed by building-destroyers.

Now that you mention it, that was what happened to me, when a goblin was on the lowered rise-bridge and it was raised it would get atomsmashed, i was wondering if the ceiling had anything to do with it...

Presence of a ceiling is irrelevant.  Creatures and items will be atomsmashed even if there's no ceiling.

What about the opposite?, a creature or thing is standing next to the wall created by the rise-bridge when it falls down does it get atomsmashed too? pushed? anything? my observations indicate that no, but I could be wrong since I wasn't in a controlled experiment when I noticed the behaviour...

Raising/lowering bridges don't do anything to creatures which are outside the space the bridge occupies.  If the bridge is a single-tile-long drawbridge and creatures are standing next to it, but not on it, raising or lowering the bridge will have no effect on them.

Another myth about draw-bridges is that when raised the wall has a weak side (inner) and a strong side (outter), building-destroyer-wise... I haven't tested this myself but it's something I've read in the forums...

I haven't seen any evidence of that.  In my fortresses, single-tile raising bridges seem to be immune to building-destroyers from any direction.  What I suspect is going on is that bridges which are longer than a single tile can be destroyed while raised if the building-destroyer can stand in the area the bridge would occupy when lowered.  I haven't tested that myself.

[benas424]

If only this worked properly... I'd fling !!BOOZE!! at goblins

[Sadrice]

Creature pit: retracting bridge that they are dumped onto and another above it to prevent fling-out before dumping the payload into the real pit...

Or just use a floor grate, which just drops items without flinging them.  Not sure about hatch covers, but I think they're the same way.

Also, how are you getting the stuff onto the bridges? I'd like to try this myself.

For my experiments I constructed floors over the bridges, then designated stockpiles on those floors.  When objects were placed in the stockpiles I designated them forbidden.  Once the stockpiles were full I cleared the stockpile designation (leaving the forbidden objects) then carefully deconstructed the floors, causing the contents of the stockpiles and the materials the floors were made from to drop onto the bridges.

There's a much easier way, just designate a garbage zone over a hole in the ceiling above the bridge and dump the items in question.

I figured out a way to make a retracting bridge conveyor, same general principle as the hall full of retracting bridges, but each bridge is a z level lower than the previous, so it goes downhill.

Spoiler (click to show/hide)

Code: [Select]

Side view:
# - wall
_ - floor
D - door
B - retracting bridge, all hooked to the same repeater/lever
= - floor grate (keeps things from being thrown back into the original room)

_<_=_________________
#xDB #############
#x_DB ############
#x__DB ###########
#x___DB ##########
#x____DB #########

Goes MUCH faster if the hallway is more than one tile wide, because an item is flung in a randomly chosen direction, and if there's a wall in the way it simply won't move.

Spoiler (click to show/hide)

Code: [Select]

representative level, top down:

#########
####X####
####D####
##BBBBB##
##     ##
#########

You can still have the input be a single tile pit, though, like this:

Spoiler (click to show/hide)

Code: [Select]

First four levels, including access floor:
a - lever linked to all the bridges
b - lever linked to safety grate 

To use, drop the stones on the grate down onto the 1x1 bridge by opening the grate, if you have not already done so, and then close the grate.  Then put lever 'a' on repeat for a while.  Alternately, instead of a grate, just drop the objects more than 3 z levels (actually, I think a single extra level would do it), and they won't come back out, allowing you to add more cargo while it's running.

z0
  #########
  #+++>+++#
  #+++++++#
  #+++=+++#
  #++a+b++#
  #########
z-1
  #########
  ####X####
  ####D####
  ####B####
  ###   ###
  #########
z-2
  #########
  ####X####
  ####+####
  ####D####
  ###BBB###
  ##     ##
  #########
z-3
    #########
    ####X####
    ####+####
    ####+####
    ####D####
    ##BBBBB##
    ##     ##
    #########

You can also make the bridges more than one tile long, which decreases the speed of object flow a bit, but moves it further horizontally for every z level dropped.

Spoiler (click to show/hide)

Code: [Select]

I leave the first level one tile long because it's narrow, and already tends to hang on to stuff for a while.

z0
    #########
    #+++>+++#
    #+++++++#
    #+++=+++#
    #++a+b++#
    #########
  z-1
    #########
    ####X####
    ####D####
    ####B####
    ###   ###
    #########
  z-2
    #########
    ####X####
    ####+####
    ####D####
    ###BBB###
    ###BBB###
    ##     ##
    #########
  z-3
      #########
      ####X####
      ####+####
      ####+####
      ####+####
      ####D####
      ##BBBBB##
      ##BBBBB##
      ##     ##
      #########

I haven't had time to try bridges 3 or more tiles long, but I think it would work, at reduced speed.

Because cargo is thrown down a z level, animals that end up in this may sustain injuries.  Throwing my livestock down a 10 level one got lots of grey wounds, though many were completely uninjured, with a red spine wound on a cavy. 

Also, you should lock the access doors.  While d-b-d-ing some stone in my food stockpiles, and accidentally marked some booze barrels.  One of my dwarves came in an access door to have a drink, and while he wasn't injured or even thrown down a level (just stunned), he did hold the door open long enough for it to get some rocks thrown into it, trapping it open.  From then on, rocks continued to get leak out that door instead of continuing down. 

Objects do sometimes get thrown back up a z level, but the general trend in the flow is forwards.  I originally designed it with alternating bridges hooked to different activators, and floor hatches between each level (also hooked to alternating activators), so that no back flow could take place, but it turned out to be unnecessary and a waste of time/mechanisms, and made it quite difficult to automate.  I still think there is some merit to that set up, as I suspect you could run it in reverse to get a (slow, prone to backflow) escalator.

As someone said earlier, in this sort of system you can not predict how long it will take any given object to come out the other end, but if you add plenty, and keep adding more, you should get a more or less continuous flow, though it takes a long time to empty once you stop adding cargo.
Also, note that these bridges are retracting, not raising.  Raising bridges would destroy pretty much all the stuff you want moved.


Ultimately, this will pretty much never be less work than just hauling whatever it is that needs moving, and thus is just a stupid dwarf trick.

[Kaos]

@ Sadrice


What does exactly your conveyor do? drop things? (I'm not being rude, just wondering if maybe I missed something)

Wouldn't be simpler to have a 2x2 hatch/grate and a <whatever amount of z-levels you want> pit, a garbage zone or stockpile over the 2x2 hatch/grate, pull a lever everything drops....

Code: [Select]

H = Hatch or Grate
# = wall
_ = Floor

      Side    Top   Mid   Bottom

Top   #HH#   ####   ####    ____
Mid   #  #   #HH#   #  #    ____
Mid   #  #   #HH#   #  #    ____
Bot   ____   ####   ####    ____


If you want to move things up, the same but the stockpile/zone is over the bottom bridge:

Code: [Select]

H = Hatch or Grate
# = wall
B = Bridge
D = Access door
_ = Floor (ceiling so things don't go up past the top level)

      Side    Top   Mid   Bottom
      ____
Top   DHH#   #D##   ####   #D##
Mid   #BB#   #HH#   #BB#   #BB#
Mid   #BB#   #HH#   #BB#   #BB#
Bot   DBB#   ####   ####   ####


[floundericiousWA]

This is a fascinating thread...

My current fortress is a hole dug into a river-plain and I've survived half a dozen goblin raids by using my goblin smashing/flinging draw bridge.  I wait until the body of goblins is approaching the bridge (guess at them being 3-5 squares away and moving full tilt) and have a burrowed civilian pull the bridge lever.  Shortly thereafter I see the bridge go up...usually two to five goblins are killed or dumped into the river immediately...usually two to five are loose in my trap maze...and the rest are stuck on the outside across the river.  Usually once or twice manages to kill several goblins, my traps and militia finish off the rest, and the unharmed goblins typically break and flee. 

This worked recently on a 40+ goblin siege (a dozen trolls, a dozen goblin archers, more than a dozen speargoblins, and the balance were axe-goblins and a thief or two) for the cost of one hammerdwarf hit with an arrow and out of commission for a couple of months.  One thing I find interesting is the possibility of flinging a goblin up on top of my walls.  I'll have to watch for that!

[Sadrice]

@kaos


my set up moves the cargo laterally by the length of the bridge for every z level down.  the loss in z levels is not the point of the thing, but rather an unfortunate consequence of the limitations of the parts available (i could do it if wall grates occpuied a tile boundary instead of a full tile).


i don't quite understand your second diagram.  i assume the second level of bridges is meant to close, catching the things thrown by the first level, before throwing them upwards again, to be caught by the hatches? i think that would require extremely finicky timing, maybe from three highly regular but slightly out of phase repeaters, but if it could be made to work, i would be very happy.

[Sphalerite]

In my last great 40d fortress (http://mkv25.net/dfma/map-8247-pagedslipped), I had a rather long bridge conveyor belt system from the drop pit trap out front to a safe collection region deep inside the fortress.  Side view of the mechanism looked something like this:

Code: [Select]

W
W
W      B      B      B      B
W     BW     BW     BW     BW
W    BWW    BWW    BWW    BWW
W   BWWW   BWWW   BWWW   BWWW
WBBBWWWWBBBWWWWBBBWWWWBBBWWWW
WWWWWWWWWWWWWWWWWWWWWWWWWWWWW

where W = solid space, and B = retracting bridges, all driven by the same repeater.  Intended direction of travel is from left to right.  The conveyor was built in a 9 tile wide trench, which was 90 tiles from start to finish.

Objects (that is, goblins and their gear) would fall into the conveyor from above.  Every few hundred cycles the bridges would all extend or retract, throwing all objects in the conveyor randomly up to 3 spaces X/Y/Z.  The vast majority of the time this would result in objects just bouncing around inside the wells.  Every now and then, one would get randomly bounced up the ramp section and travel over the cliff to the next well.  Because of the way the wells were shaped, objects could never pass backwards into a prior well, so the cliffs acted like a ratchet to prevent backwards movement.  With enough time and random motion, all the items in the conveyor would eventually end up at the finish.

It took on average about a year for objects to travel the entire length of the conveyor, and it caused a massive FPS drain every time it triggered from all the thousands of objects flying around.

A downward staircase conveyor like Sadrice proposed would have been much more efficient, but this was back in the day of 40d where I only had 15 Z-levels underground to work with.  Today if I was to build a conveyor I'd take advantage of the extra Z-levels and use gravity to help.

[Kaos]

@kaos

my set up moves the cargo laterally by the length of the bridge for every z level down.  the loss in z levels is not the point of the thing, but rather an unfortunate consequence of the limitations of the parts available (i could do it if wall grates occpuied a tile boundary instead of a full tile).

Oh! it's horizontal movement!!  well almost....



What about something like this then?:

Code: [Select]

B = Retractable Bridge
D = Door or Wall Grate or Verical Bar or Flood Gate (maybe Window)
# = wall
_ = Floor (ceiling so thing don't go up)
____________
#BDBDBDDBDB#
############
011223344550movement from left to right, the numbers at the bottom are for reference,
Step 1: all the doors open,
the first bridge retracts/extends,
things get flung up to door 2, nothing up because of the ceiling nothing back because of wall/locked door/whatever solid


Step 2: Door 1 closes, repeat Step 1 with bridge 2....


and so on, until thing get to Bridge 5, alternatively it can work backwards too...

i don't quite understand your second diagram.  i assume the second level of bridges is meant to close, catching the things thrown by the first level, before throwing them upwards again, to be caught by the hatches? i think that would require extremely finicky timing, maybe from three highly regular but slightly out of phase repeaters, but if it could be made to work, i would be very happy.

Yes, the bottom most bridge retracts/extends some thing will get flung up since there's no where else to go, the upper bridge has to close so it catches the flung up things before the fall back again, and so on up to the top where instead of a bridge you can have a Hatch/grate if you want the room to be open, if you use a bridge it had to be in a walled room with ceiling, so things don't get flung away from the landing zone that could be a stockpile...

[Sphalerite]

What about something like this then?:

Code: [Select]

B = Retractable Bridge
D = Door or Wall Grate or Verical Bar or Flood Gate (maybe Window)
# = wall
_ = Floor (ceiling so thing don't go up)
____________
#BDBDBDDBDB#
############
011223344550movement from left to right, the numbers at the bottom are for reference,
Step 1: all the doors open,
the first bridge retracts/extends,
things get flung up to door 2, nothing up because of the ceiling nothing back because of wall/locked door/whatever solid

More likely, things get flung from bridge 1 onto the space occupied by door 1.  Door 1 cannot close now, because there is an object in the way.  The objects in that space never move again, because they aren't resting on a retracting bridge.  Eventually, all the objects in your conveyor are sitting on stuck-open doors and will never move again.  A conveyor system can't be allowed to have any spaces where objects can come to rest that aren't paved with retracting bridges.  And no, you can't have a retracting bridge and a door occupying the same space.

Yes, the bottom most bridge retracts/extends some thing will get flung up since there's no where else to go,

It doesn't work that way.  Objects flung by a bridge decide which way they're going to get flung before they check if there are any obstacles in the way.  If the only way an object can go is upwards, the majority of the objects simply won't move at all - they'll start moving sideways or down, immediately hit an obstacle, and then stop.  With your vertical arrangement of bridges, most of the objects on each bridge will fall downwards when the bridge opens, rather than upwards.

[Sphalerite]

It is possible to build a peristaltic conveyor mechanism using bridges and doors with the following design:

Code: [Select]


WWWWDb
WWWDbW
WWDbWW
WDbWWW
WbWWWW


where b = open tile with single-tile retracting bridge, D = door floating over empty space, and W = solid rock or walls.  This requires you to use the trick where you build a wall, build a door on top of it, and then deconstruct the wall, leaving the door floating in mid-air.

The objects to be moved are first placed on the lowermost bridge on the left.

To run the conveyor, open door number one (furthest to the left), then retract or extend bridge the bridge under it.  Most of the objects on the bridge will go nowhere, but some of them may be thrown onto the second bridge.  Objects which are thrown upwards into the tile containing the open door number one will fall back down onto the bridge.  Next, close door number one and open door number two, then extend or retract bridge number two.  Most of the objects will go nowhere, a few will be thrown onto bridge number three, but none will be able to fall back on to bridge number one because the closed door number one will block them.  Repeat this process for each of the bridges, and run the entire cycle over and over again, and objects placed at the beginning of the conveyor will gradually be moved upwards along the conveyor mechanism.

[Graebeard]

Brilliant.