... Could you diagram that? I'm not easily picturing how the cave-in works. ...
(probably ninja'ing thegoatgod_pan, but hey, i like ascii diagrams)
The way I do the controlled cave-in is: (as seen in game)
Diagram Legend
▓ - natural wall
≈ - paved floor (can be any kind of floor, really)
+ - constructed floor
· - empty space
┼ - bait door
I - support
Original upper floor
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
Upper floor channeled out
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
Before-Support upper level, with constructed floors
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
▓·······≈≈≈≈≈≈≈≈
▓·++++++≈≈≈≈≈≈≈≈
▓·++++++≈≈≈≈≈≈≈≈
▓·++++++≈≈≈≈≈≈≈≈
▓·++++++≈≈≈≈≈≈≈≈
▓·++++++≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
Lower level (direction of monster travel, left to right)
▓▓▓▓▓▓▓▓▓
▓≈≈≈≈≈≈≈▓
▓≈≈≈≈≈≈≈▓
▓▓▓▓▓▓▓▓▓≈≈≈≈≈≈≈▓▓▓▓▓▓▓▓▓
≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓≈≈≈≈≈≈≈▓▓▓▓▓▓▓▓▓
▓≈≈≈≈≈≈≈▓
▓≈≈≈≈≈≈≈▓
▓▓▓▓▓▓▓▓▓
Lower level with support & bait doors built
▓▓▓▓▓▓▓▓▓
▓≈≈≈≈≈≈┼▓
▓≈≈≈≈≈≈≈▓
▓▓▓▓▓▓▓▓▓≈≈≈≈≈≈≈▓▓▓▓▓▓▓▓▓
≈≈≈≈≈≈≈≈≈≈≈≈I≈≈≈≈≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓≈≈≈≈≈≈≈▓▓▓▓▓▓▓▓▓
▓≈≈≈≈≈≈≈▓
▓≈≈≈≈≈≈┼▓
▓▓▓▓▓▓▓▓▓
Prepared Upper level, after support built below, deconstructed nearest constructed floors to right edge:
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
▓·······≈≈≈≈≈≈≈≈
▓·+++++·≈≈≈≈≈≈≈≈
▓·+++++·≈≈≈≈≈≈≈≈
▓·+++++·≈≈≈≈≈≈≈≈
▓·+++++·≈≈≈≈≈≈≈≈
▓·+++++·≈≈≈≈≈≈≈≈
▓·······≈≈≈≈≈≈≈≈
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
Now just tie a lever to the support, and wait for the monster to bash on the bait doors. Pull the lever, cave-in kills monster.
To reset, rebuild the constructed floors above, rebuild the support, deconstruct the nearest constructed floors, and re-tie the lever to the support.