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0001579Dwarf FortressDwarf Mode -- Buildings, Machinespublic2010-04-27 09:182010-07-09 21:28
Toady One 
0001579: Obsidian has two melting points, ambigious magma-safeness
I tried controling magma flow two times on two seperate locations.

The first instance was a simple unpressurized magma duct flowing from a pipe to an empty pit I'm trying to fill with obsidian. The control method I used was two adjoining doors; one was a mica door, the other obsidian. The mechanisms used was bauxite for the mica door, and obsidian for the obsidian door. However, abut 6 minutes later when I decided it was time to plug the flow, I found out the obsidian door was nowhere to be found. I pulled the lever but only the mica door responded; the obsidian door was apparently nowhere to be seen. DF Wiki states that obsidian is magmasafe, so I simply loaded a save and tried again. Still to no avail. Again the mica door was intact but the obsidian door was missing. I noted that the mica door was south to the obsidian door.

Second instance was on top of a giant magma pipe stack rising 54 z-levels from the top of the magma pipe to the ground level artificial magma reservoir. I installed 5 nickel floodgates on the deposit duct, all installed with obsidian mechanisms. I saved as a backup and pulled the lever for both the dwarven reactor(!) and the floodgates, and went on with my other fort building business. I checked back about ten minutes later only to find four of the five floodgates deconstructed. One was floating around on the magma reservoir I was filling up, two were floating on the exit duct(where they are supposed to be, but not as a building but as a free furniture, as if on a stockpile), while the last one was still intact. I am very, VERY certain that all five floodgates are nickel and all ten mechanisms used are obsidian. I reloaded the save and tried again. The same exact thing happend: one floodgate remained standing and responsive to the lever while four floodgates floated around. One even managed to open the forbidden schist door that originally provided access for my masons, flooding the entire access shaft for the pump stack with magma. I again noted that the only remaining floodgate was the southernmost one. I know it sounds like just a coincidence, but one can never know.

Please do note that prior to placing the floodgate setup I dug a small 3x3 channel as a testing area and placed a single nickel floodgate with obsidian mechanisms attached. I flooded the channel with magma, pulled the lever, made sure the floodgate was in the open(invisible) position, and left it that way for a whole season. When Spring arrived and I pulled the lever again the floodgate responded perfectly, so I am quite certain both nickel and obsidian are magmasafe. This gave me the impression that this strange phenomenon only happens in flowing magma.

In a very similar setup, but this time with water, such strangeness did not happen. I even left the water door open for a year behind a fully pressurized pump under full flow, but the door withheld.

I have just force-quit DF in frustration before writing this. After writing I'm going to try the floodgates again for a third time. Maybe I'll leave the flow on for longer periods to see if the single intact floodgate follows suit.

If this is confirmed to be a bug, I'll have no way of building the obsidian monolith I had planned...
Use pumps or channels for magma. Install doors or floodgates (the materials I used so far was mica, bauxite, obsidian, and nickel, so I don't know if the phenomenon is material-specific or universial). Link them to levers(make sure they are magmasafe). Open them and let magma flow through. After a while(it does take a while; in my case it was the time it takes to fill 500+ tiles with 2/7 magma) try closing the door/floodgate system. Or simply just check with the look tool to see if the buildings are still there.
If this is not a bug, but instead an intended feature, please let me know.
Issue History
2010-04-27 09:18meto30New Issue
2010-04-27 09:31smjjamesNote Added: 0005345
2010-04-27 09:34meto30Issue Monitored: meto30
2010-04-27 09:34meto30Issue End Monitor: meto30
2010-04-27 09:37meto30Note Added: 0005348
2010-04-27 09:47meto30Note Edited: 0005348bug_revision_view_page.php?bugnote_id=0005348#r1903
2010-04-27 10:04Logical2uNote Added: 0005350
2010-04-27 10:16DoctorZuberNote Added: 0005353
2010-04-27 10:19DoctorZuberNote Edited: 0005353bug_revision_view_page.php?bugnote_id=0005353#r1905
2010-04-27 10:20DoctorZuberNote Edited: 0005353bug_revision_view_page.php?bugnote_id=0005353#r1906
2010-04-27 10:30DoctorZuberNote Edited: 0005353bug_revision_view_page.php?bugnote_id=0005353#r1907
2010-04-27 10:58meto30Note Added: 0005363
2010-04-27 11:14meto30Note Edited: 0005363bug_revision_view_page.php?bugnote_id=0005363#r1913
2010-04-27 12:05QuietustNote Added: 0005368
2010-04-27 12:21QuietustNote Edited: 0005368bug_revision_view_page.php?bugnote_id=0005368#r1918
2010-04-27 12:32FootkerchiefNote Added: 0005370
2010-04-27 12:32FootkerchiefIssue Monitored: Footkerchief
2010-04-27 12:34FootkerchiefNote Edited: 0005370bug_revision_view_page.php?bugnote_id=0005370#r1920
2010-04-28 01:22meto30Note Added: 0005487
2010-04-28 01:55meto30Note Added: 0005493
2010-04-28 02:02meto30Note Edited: 0005493bug_revision_view_page.php?bugnote_id=0005493#r1991
2010-04-28 02:03meto30Note Edited: 0005493bug_revision_view_page.php?bugnote_id=0005493#r1992
2010-04-28 04:36Logical2uNote Added: 0005508
2010-04-28 04:49Logical2uNote Edited: 0005508bug_revision_view_page.php?bugnote_id=0005508#r2005
2010-04-28 06:24meto30Note Added: 0005515
2010-04-28 06:55Logical2uNote Added: 0005520
2010-04-28 09:23FootkerchiefIssue End Monitor: Footkerchief
2010-04-28 09:27smjjamesNote Added: 0005544
2010-04-28 10:07FootkerchiefTag Attached: PROBABLE QUICK FIX
2010-04-28 10:39Logical2uSummaryFlowing Magma keeps destroying doors or floodgates - not melting, but removing(deconstructing) => Obsidian has two melting points, ambigious magma-safeness
2010-04-28 10:39Logical2uSteps to Reproduce Updatedbug_revision_view_page.php?rev_id=2027#r2027
2010-04-28 13:20DoctorZuberNote Added: 0005569
2010-04-28 13:29smjjamesNote Added: 0005572
2010-04-28 13:37FootkerchiefNote Added: 0005574
2010-04-28 13:41FootkerchiefNote Edited: 0005574bug_revision_view_page.php?bugnote_id=0005574#r2046
2010-04-28 17:43DoctorZuberNote Added: 0005608
2010-04-29 11:27meto30Note Added: 0005672
2010-04-29 11:29meto30Note Edited: 0005672bug_revision_view_page.php?bugnote_id=0005672#r2082
2010-04-30 15:59LeononIssue Monitored: Leonon
2010-06-06 05:38Toady OneNote Added: 0007785
2010-06-06 05:38Toady OneStatusnew => resolved
2010-06-06 05:38Toady OneFixed in Version => 0.31.06
2010-06-06 05:38Toady OneResolutionopen => fixed
2010-06-06 05:38Toady OneAssigned To => Toady One
2010-06-07 21:52FootkerchiefTag Detached: Probable Quick Fix
2010-06-09 06:45Toady OneStatusresolved => closed
2010-06-09 07:56FootkerchiefStatusclosed => resolved
2010-07-09 21:28TomiTapioTag Attached: melting

2010-04-27 09:31   
Since you had used mechanisms, I would have said that was the problem, but you said they are magmasafe, so dunno.

Are you absolutely sure the doors didn't melt?

Anyways, a save would definetly be of use even though you provided alot of detail.
2010-04-27 09:37   
(edited on: 2010-04-27 09:47)
I'm very new to the bug tracker, so could you kindly teach me how to upload files? I see only a 'monitor' button below the attached files section.

I am sure that at least the floodgates didnt melt. The original floodgates that fell down to the reservoir are still there, fully visible. Also, please note that this does NOT happen on ALL floodgates - one of them is intact, even as we speak.

PS: I've resorted to using DFHack to fill the obsidian pits. Magma floodgates still not working.

2010-04-27 10:04   
You can use the Dwarf Fortress File Depot to upload files. http://dffd.wimbli.com/ [^]

There has been some strangeness reported on the forums about magma and magma safe material interaction, specifically with regards to Nickel, although it appears this is the first bug report on the issue.
2010-04-27 10:16   
(edited on: 2010-04-27 10:30)
magma and obsidian are not a magma-safe materials, or at least, they were not in 40d. It worked before because un-mined rock was always safe, and constructions are always safe. a constructed wooden wall would stop magma. So would a tree.

I haven't checked to see how the mechanics on this have changed in the new version and I'm taking the updated wiki with a grain of salt for now.

It's also possible that the temperature of magma may have changed.

2010-04-27 10:58   
(edited on: 2010-04-27 11:14)
The true strangeness that baffles me is that the 'test floodgate' placed in static magma does not deconstruct as the ones in the ducts did. And yes I did pull the lever to 'open' the test floodgate. As far as I know obsidian mechanisms don't melt. Or maybe I'm wrong... argh, at least I can use DFHack now to pour magma and water. Faster, even.

Uploaded save: http://dffd.wimbli.com/file.php?id=2250 [^]

2010-04-27 12:05   
(edited on: 2010-04-27 12:21)
Obsidian should definitely be magma-safe in 0.31 - it has the exact same melting point as bauxite. Also, a quick test using dtil with a hastily hacked memory.ini (enough to get it to connect to Dwarf Fortress 0.31 and activate the Tile Editor) indicates that magma is still temperature 12000, even when exposed to the air.

A quick search through the raws suggests another possibility, though - fire snakes have a FIXED_TEMP of 14000, which is hot enough to melt everything but periclase, dolomite, and [raw] adamantine.

2010-04-27 12:32   
(edited on: 2010-04-27 12:34)
The fire snakes are a very interesting theory. meto30, you could try modding the fire snake's temperature down to 12000 (in the save folder's raws) and see if you still get your buildings destroyed by flowing magma.

2010-04-28 01:22   
Quietust, Footkerchief, I will try that out immediately. Thank you for the advice, by the way.

It is unfortunate that I probabily live on the opposite side of the globe from you guys, as this means nearly all communication will have a delay of a half-day.
2010-04-28 01:55   
(edited on: 2010-04-28 02:03)
On the fifth try the four floodgates again disintegrated as before, but as I was looking at the scene I realized that the only floodgate that never got destroyed, the southernmost one, was attached to not obsidian, but BAUXITE mechanism. All the above four are obsidian. How could I have missed this? I thought I made sure that all five were obsidian (and all the lever-side mechanisms are, by the way, so I think my fingers slipped when choosing material).

Checking back at the original scene with two doors, the only door left standing uses mica mechanisms(and is a mica door... but I thought that one used bauxite.....). The other door, as I recall, was all obsidian, so this gives me one conclusion.

OBSIDIAN is NOT MAGMA SAFE..... God, I feel so stupid...

I'll try reinstalling the floodgates with mica mechanisms(I ran out of Bauxite I embarked with) and see if it solves the problem.

PS: I checked the RAWs. Obsidian is listed with TWO MELTING POINTS. The one above lists 13600, same with bauxite, but the lower one(which I missed before) lists... 11818. So, obsidian melts in magma. ...................Oops. OK. Close this report, please. I'll just bash my head with a Hammer and hope the King does not dispose me for non-dwarf-like ignorance of rock charateristics...

PSS: Which again leaves doubts. Why did the test floodgate survive for so long? Perhaps 2/7 magma and 7/7 magma(flowing) have different melting properties?

2010-04-28 04:36   
(edited on: 2010-04-28 04:49)
Well the issue now seems to be that obisidian has two melting points. And only one of them is respected - the lower one, it would seem. There's still a bug here, but it's not quite as bad as it could be.

Edit: Did you discover that any stone listed as Magma safe on the Wiki caused problems other than obsidian? If not, I'll change the report to reflect this.

2010-04-28 06:24   
currently tested for Mica, Obsidian, and Bauxite. Obsidian melted, Mica and Bauxite did not. My map has very little variety in terms of stone (-1~-10 z-levels are almost entirely orthoclase and schist, while those below is a mix of microcline, diorite, mica, and granite. I do not have any extensive mining operations under the -20 mark because the first cavern is nearly entirely flooded and infested with animals), but I'll try to obtain as much variety as I can.

By the way I fixed the floodgate problem by deleting the lower melting point on obsidian. Now the floodgates work flawlessly.
2010-04-28 06:55   
Ok, thank you for testing! I'm glad that it's as quick a fix as removing the duplicate.

Would you like me to change this bug report to reflect the error in Obsidian RAWs, since it seems like that's the main issue?
2010-04-28 09:27   
Sounds like a good idea if its one of those quick fix things. I removed the duplicate myself when I heard of this.
2010-04-28 13:20   
In the process of looking into this issue I've noticed that MANY stone types have no entry for melting point and/or boiling point in the raw files. That seems a bit odd to me. Does this mean those stones can never melt?
2010-04-28 13:29   
I believe those simply default to whatever the default melting point is.
2010-04-28 13:37   
(edited on: 2010-04-28 13:41)
The default melting point, like all other properties not explicitly set by the individual stone types, is set in STONE_TEMPLATE in material_template_default:


2010-04-28 17:43   
ah okay, well I learnt sumptin' ... Thank you Footkerchief.
2010-04-29 11:27   
(edited on: 2010-04-29 11:29)
Yes, I'd like the report changed to reflect the duplicate entry, with an emphasis on the very quick fix(i.e. removing one of them).

This is the most extensive obsidian-casting I've done. And I've just learned that stones encased in cooling lava reappear when I dig out the obsidian. Strange...

PS: Ah, the edit is already applied. I didn't notice that when i wrote this note. Thank you.

Toady One   
2010-06-06 05:38   
I kept the higher melting point. The other one is probably closer to the accurate range, but I'm keeping a higher melting point than the fluid lava as weird as that is until such a time as we can play more with lava cooling effects etc.