I thought it might be useful to have a quick tutorial on the various (d)esignations, so I set to write one, 30 minutes ago. It appears to have grown out of all proportion, but here you are anyway. (Any big errors/omissions in it that need sorting, those who already know?)
All of the main mining (d)esignations apply to natural floors, walls, ramps, etc. See at the end for constructed floor, walls, ramps, etc needing to be removed, and workshops'/furnitures' own administration menus for their own deconstruction methods.
(d)esignate (d)igging - a.k.a. 'mining'. Affects single level, rock 'wall', only.
###### ######
##_### < existing tunnel (in/out of page) ##_### < existing tunnel still has floor
###### <--- layer to be D-Ded #_____ <--- Floor looks the same, regardless
## ## < top of open space/cavern ## ## < Unaffected
## ## ## ##
Note that if the "#" being dug through is the sole support for any natural and/or constructed 'mass' above it, then cave-in will occur. But something supported sideways will stay until/unless the floor is removed by one of the other methods.
(d)esignate c(h)annel - Primarily affects floor on designated level, but will also affect any natural 'wall' on this level and on the level below.
Open topped, solid and non-solid ground
123 123 Channeling at ground level below 1 and 3
________ ___ _ __ On this level, floor is removed, reveals "down ramp" (down-triangle symbol) to level below if previously solid
####__## -> ###\__## On this level, any 'wall' block is removed and becomes "up ramp" (up-triangle symbol)
######## ######## Noting that (unless otherwise supported, by in/out-of-page connections, "2" would now cave in!
Open topped, edge of pit
1 Set to channel at ground level below 1
___ __ __ __ On this level, floor is removed, reveals new "down ramp", old "down ramp" gone if that was last adjacent wall
###\__## -> ##\___## On this level, affected 'wall' becomes "up ramp" and old "up ramp" goes (ditto)
######## ########
In the middle of rock
1 2 3 1 2 3
####### #######
######_ ##### _ Channelling at '3' on this level removes wall and floor leaves 'drop' to level below, no ramp/walkability
###___# ### __# Channelling at '2' on this level removes floor and wall on level below, replaces with ramp connection
##_#### -> # _/### Channelling at '1' on this level mines out both walls here and below, replaces with ramp connection
_###### _/#####
####### #######
(d)esignate upward-(r)amp
No need for additional diagrams (?), just take all of the c(h)annelling examples from the above set that create ramps, but imagine you designated a (r)amp on the level below.
Access to the (r)amping level is not always necessary (can be worked on as if a channel on the layer above), but if you (r)amp under a tree (or a sole piece of supporting rock-wall), you will cause a cave-in.
(d)esignate (u)pward stairway (shown by a "<" symbol)
(d)esignate (j) - for downward stairways (shown by a ">" symbol)
(d)esignate (i) - for up-down stairways (shown by an "X" symbol)
12 12
####### #######
___#### __>>### D-J at 1 or 2, creates viable down-stairs to connect to up(/+down?) stairs on level below, but below 2 would need /constructed/ stairs
###____ -> ##X>___ D-I at 1 creates up-down stairs, but you can only D-J at 2 to create (unconnected) down-stairs. But you can use constructions to turn into up/down (or /just/ up) later
###____ ##<____ D-U into the wall at 1 will connect to any (part?-)down stairs on the level above, you would need to /construct/ up-stairs at 2
####### #######
(d)esignate (z)-removal - i.e. removes (natural) up-stairs or ramps
Here we're starting with a stairwell (">" downwards stairs, "X" up-down stairs
on level below, and "<" upwards stairs on level below that) to one level and a
ramp access to an intermediate level.
1 2 1 2
####### #######
__>_ ## __>_ ## Nothing directly affected on this level, but access may be lost to level below
##X#\__ -> ##>#___ The up-down stairwell below 1 becomes a down-only stairway (to nowhere?), the ramp becomes a floor
##<____ ##_____ If applied to the up-stairwell, it becomes normal floor and access is lost.
####### #######
(d)esignate fortific(a)tions - create structurally intact, but at least partially visually/ballistically/fluidically empty block
1 1
##### #####
#____ H____ D-A on wall under 1 will create a fortification that can be seen through and shot through.
## ##### -> ## ##### (both directions for higher skill levels, but mainly inside-outwards.
~~~#____ ~~~H____ D-A on wall under 1 will let the liquid (water or magma!) next to it flood into the tunnel!
######## ######## (when full on both sides, creatures /may/ be able to pass through
Note, this is not a "Mining" job, but a "Stone Engraving" job, a subset of the Masonry job-group, by one name or another according to context.
It may also only be designated on natural walls that are 'pre-smoothed' by the (d)esignate-(s)mooth job (see below), also the responsibility of Engraver dwarfs.
Also available are:
(d)esignate (t)ree-felling - Only applies to trees, and woodcutters
(d)esignate (p)lant-gathering - Only applies to harvestable (naturally-growing, non-withered) plants, and herbalist/plant-gathering dwarfs
(d)esignate (s)mooth stone - Sets exposed natural walls and floors to be engraved 'smooth' by stone engravers
(d)esignate (x) - Removes all designations across the selected area.
(d)esignate remove co(n)struction - If a (b)uilt (c)onstruction is on that spot, set it to be removed.
On the whole, works the same as mining out an existing wall/stairway/floor/whatever by the appropriate command (including the danger of cave-ins when this is the sole support!) but (b)uilt and (c)onstructed (w)alls do not leave a floor tile if set to be built over an open space (including channel and down-ramp, or spot where a constructed wall existed on the layer below (and there was no natural floor on this one) but has now itself been deconstructed. You cannot have built a wall on top of a (b)uilt (c)onstruction of type (f)loor, but you can have put a constructed floor over either a natural or a wall-top floor.
There are also two designations that a further level of menu (the block forbid/reclaim/etc one and the traffic zone one) , but I've gone on for too long already, and they deserve their own teatise (and, like the above, have probably been explained so many times before, anyway!)