Dwarf Fortress Bug Tracker - Dwarf Fortress
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0007121Dwarf FortressVegetationpublic2014-07-12 02:082021-07-16 17:42
0007121: Cutting down mushroom trees leaves floating ramps of indeterminate material
Cutting down giant cave mushrooms (tower-cap, goblin-cap, black-cap, etc.) frequently leaves behind a ring of floating ramps. This happens on every 'cap that has ramps on it (simply labeled tower-cap cap on loo(k) view.)
Cut down any giant shroom that has ramps on the cap in dwarf mode.

May be limited to shrooms that have their caps against cavern ceiling.
The ramps are single-tile - they do not have corresponding ramp either above or below.
No tags attached.
related to 0001573confirmed Footkerchief Underground trees leave behind soil floors when cut down 
related to 0001547confirmed Footkerchief Cave-ins can leave hanging down ramps in air 
has duplicate 0008084resolved lethosor Subterranean trees leave unusable ramps behind. 
Issue History
2014-07-12 02:08KumquatNew Issue
2014-07-14 07:19TalvienoNote Added: 0026317
2014-07-14 07:20TalvienoNote Edited: 0026317bug_revision_view_page.php?bugnote_id=0026317#r9807
2014-08-13 15:31MrCNote Added: 0028993
2014-08-13 15:35FootkerchiefRelationship addedrelated to 0001573
2014-08-13 15:35FootkerchiefAssigned To => Footkerchief
2014-08-13 15:35FootkerchiefStatusnew => confirmed
2014-08-18 10:05TalvienoNote Added: 0029233
2014-08-19 21:14TalvienoNote Edited: 0029233bug_revision_view_page.php?bugnote_id=0029233#r11268
2014-08-20 04:55lethosorRelationship addedhas duplicate 0008084
2014-11-22 07:17ptb_ptbNote Added: 0031116
2014-11-22 07:18ptb_ptbNote Edited: 0031116bug_revision_view_page.php?bugnote_id=0031116#r12381
2014-11-22 07:21ptb_ptbNote Added: 0031118
2014-11-24 07:04FootkerchiefRelationship addedrelated to 0001547
2017-04-19 16:22anewanameNote Added: 0036433
2017-04-19 16:22anewanameNote Edited: 0036433bug_revision_view_page.php?bugnote_id=0036433#r14703
2017-04-23 12:00LociNote Added: 0036447
2017-06-08 18:32HuntthetrollIssue Monitored: Huntthetroll
2017-11-29 20:28DwarfuNote Added: 0037125
2017-11-29 20:28DwarfuStatusconfirmed => resolved
2017-11-29 20:28DwarfuFixed in Version => 0.44.01
2017-11-29 20:28DwarfuResolutionopen => fixed
2017-11-29 20:28DwarfuAssigned ToFootkerchief => Toady One
2017-11-30 14:15LociNote Added: 0037145
2017-11-30 14:15LociAssigned ToToady One => Loci
2017-11-30 14:15LociStatusresolved => confirmed
2017-11-30 14:15LociResolutionfixed => open
2017-11-30 14:15LociFixed in Version0.44.01 =>
2017-11-30 14:15LociDescription Updatedbug_revision_view_page.php?rev_id=14983#r14983
2017-11-30 14:15LociSteps to Reproduce Updatedbug_revision_view_page.php?rev_id=14985#r14985
2017-11-30 14:15LociAdditional Information Updatedbug_revision_view_page.php?rev_id=14987#r14987
2017-11-30 15:01DwarfuNote Added: 0037147
2017-11-30 15:02DwarfuStatusconfirmed => needs feedback
2017-11-30 17:47mrmagolorNote Added: 0037152
2017-11-30 22:17LociNote Added: 0037155
2017-11-30 22:17LociStatusneeds feedback => confirmed
2017-12-01 07:33DwarfuNote Added: 0037161
2021-07-16 17:42BumberNote Added: 0041099
2021-07-16 17:43BumberNote Edited: 0041099bug_revision_view_page.php?bugnote_id=0041099#r16722

2014-07-14 07:19   
(edited on: 2014-07-14 07:20)
Can confirm this. It's not limited to those that have caps against the cavern ceiling - I cut some down at the bottom of a deep pit and had the same thing occur.

2014-08-13 15:31   
Also confirming this glitch.
2014-08-18 10:05   
(edited on: 2014-08-19 21:14)
Can confirm that this still happens in 40.09.

Edit: Here's an interesting addition: if a tree grows back in its place, like a spore tree, fungiwood, or blood thorn, the ramps change color to match the color of the new tree, but the tiles aren't updated.

2014-11-22 07:17   
(edited on: 2014-11-22 07:18)
There is similar behavior where unusable down slopes and vermin colonies are left floating in the air after large cave-ins.

Save file (before cave in):
http://dffd.wimbli.com/file.php?id=10110 [^]

See 0008573 for how to cave in the left hand side of the map.

2014-11-22 07:21   
I think this is related to, or duplicate of
2017-04-19 16:22   
I have observations and speculation to add to this. In the dffd save below, there is a dwarf busy chopping a tree, where the tree's ramp was part of the route up to the fortress. A few seconds after the tree fell, I did 'b''C 'W' and as shown in this image (http://imgur.com/a/wcOti [^]), the distance to the materials is a negative number. Whether the wall was placed or not, FPS dropped from the cap of 50 to 4, for ten or twenty minutes, and there was much eat/drink job cancel spam, then the FPS returned to 50.

In comparison, if you 'd' 'x' the tree and 'd' 'z' that staircase, there is no FPS hit or job cancellation spam. My speculation is that these half-ramps (and the half-ramps in issue 0001547, possibly from upon-embark cave-ins) might effect pathing of fortress invaders (FBs, booze-thieves, etc) and cause some of those sudden FPS drops that players run into.

The game is 43.05 x64 from linux with MayDay tileset and no mods or dfhack used.
http://dffd.bay12games.com/file.php?id=12847 [^]

2017-04-23 12:00   
@anewaname: Thank you for the save. The negative distance bug is a continuation of 0004372, which I have split out to 0010208.
2017-11-29 20:28   
These mushrooms don't have ramps as of 44.01.
2017-11-30 14:15   
Yes they do, and they're still buggy as described above. Here's a before/after screenshot in v0.44.02:

http://dwarffortresswiki.org/index.php/File:Ramp-remnants.png [^]
2017-11-30 15:01   
Was that generated in 44.02? My game is unmodified and I’m looking at those mushrooms and they don’t have ramps and they cut down cleanly.
2017-11-30 17:47   
I had this happen to me in 0.44.01.
2017-11-30 22:17   

Yes. How tall are your caverns? Mushroom trees seem to require at least 3 z-levels to produce ramps, and 4 z-levels to produce the problematic down-ramp tiles.
2017-12-01 07:33   
That’s exactly what it is. After looking over the caverns to try and narrow it down (because I certainly had the bug in previous versions), I see that although the caverns meander through 4-5 z-levels, at no point within them is there more than 2 z-levels available growth space.

I didn’t see anything in this report related to their size, but at least we’ve recorded the distinction now.
2021-07-16 17:42   
(edited on: 2021-07-16 17:43)
I was reverse engineering tree-cutting code and think I found the cause of this. When removing the tree's tiles, it iterates from the top down. If there's an up ramp below the tile to be removed, it puts a down ramp in the tile (replacing the tree's down ramp with another down ramp.) It then proceeds downwards and removes the up ramp tile (because it's part of the tree,) and so on until it reaches the ground.

The simple fix is to check if the up ramp below is part of the tree, and put empty space instead of a down ramp if it is.