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Author Topic: Smoke, chimneys, and fuel use  (Read 228 times)

Andeerz

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Smoke, chimneys, and fuel use
« on: November 30, 2025, 11:12:47 pm »

Some or all of the ideas in this post have been suggested many times, but not recently.  I figured I'd start a new thread here, especially since the recent Siege Update has made these ideas all the more tantalizing to me.  This, and poop/waste.  But that is for another time.

The suggestions are as follows:

1. To simulate the harmful gaseous byproducts produced by these things in real life, furnaces, kilns, and other workshops that use (or in the future, might use) fuel for heating or burning things should produce smoke (for lack of a better approximation).  This should occur while the job at the workshop is being completed.  Where the smoke arises should be designated in the raws that define the workshop layout.  For example, smoke could be made to originate at the north-most center tile of the smelter workshop where it looks like it should.  The tiles surrounding this tile should either be made impassible to smoke, again defined in the raws.  Or the tile should behave like the chimney/pipe tile suggested later on (see suggestion 3).  This might need some further thought, though.

2.  Related to this, smoke physics needs to change a bit for this to work in a way that isn't just cosmetic and that will require the player to make some functional design choices in fortress layout.  While doing some !!SCIENCE!! I learned that miasma and smoke behave a bit differently.  Smoke, once it propagates upward, doesn't propagate downward.  Miasma seems to do so, though.  I suggest smoke behaves more like miasma, but propagating upward more frequently than downward.  I also suggest smoke diffusing more widely hanging around longer than it does presently for a given unit of smoke.

3.  Introduce a chimney/pipe construction that only allows propagation/flow of fluid through it in a given direction and is impassible to anything else (though, maybe not vermin?).  This could conceivably be placed where the smoke comes out of the workshop (see suggestion 1) and built in tandem with other pipes to direct where the smoke goes out.  This could also be useful for directing other fluids.

4.  In order to simulate the requirements of fresh air and upward draft for furnaces without revamping the physics of the game with more complicated and resource intensive modeling of fluids, I suggest at least non-magma smelters, kilns, and glass furnaces require an unobstructed path (perhaps not exceeding a certain length) to the outdoors from where the smoke comes out of the workshop (see suggestion 1) or chimney (suggestion 3).  From my understanding, this wouldn't require too much overhead, no?  I mean, the workshop could check maybe every 100 ticks or so to see if the path is still clear.     

5.  Sort of unrelated... Make kilns and glass furnaces able to use wood as a fuel.  And kitchens, for that matter, if they ever come to need fuel.  These don't require a reducing environment to function, so using charcoal, while it still should be available as an option, is a real waste.  To do this, I suggest that, at least, the [FUEL] token in the raws be changed so that one can specify what fuel is permitted in reactions.

This might sound like a big change, but this is largely already possible with some DFHack scripting (at least suggestion 1 is).  The only obstacle so far from my attempts is suggestion 2.  If the physics of smoke changed, it would be possible to kludge it in with existing tools by the modding community.  Anyway, with all these suggestions in place, it might make for some really interesting gameplay, in my opinion, especially with the new difficulties introduced with the new Siege Update.  No longer can you just have your smelters and furnaces nestled in the same area as everywhere else without making some sort of compromise beyond access to stockpiles.  You need to have some rudimentary ventilation considerations if it is going to be located indoors somewhere.  I think this would be neat and is already within reach. 
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Starver

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Re: Smoke, chimneys, and fuel use
« Reply #1 on: December 01, 2025, 01:00:35 am »

Bear in mind that 'effluent' (for water, with its necessary infrastructures) is generally considered a no-no, under Tarn's aegis. A lot of the suggestion parallels sewerage suggestions (especially the plumbing and fresh-in/waste-out parts), except for being a 'waste gas' scenario instead, so some of the reasons why the former is unlikely might apply to the latter.

Andeerz

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Re: Smoke, chimneys, and fuel use
« Reply #2 on: December 01, 2025, 03:59:30 am »

Well, in the case that Tarn et al. don't want this, I sure as heck hope the game gets opened up enough that this can be modded in easily.  It looks like it might get that way.  :)

I will try to find what Tarn has said about why effluent is considered a no-no.  The most I can recall is a hesitancy voiced in a single future of the fortress post a long time ago, I think, and that it wasn't a definitive yes or no.  Forgive me, but do you happen to know off the top of your head where to find this info?  In any case, it is curious that brown and yellow filth are still present in the recesses of the game...  If it is a time allocation issue on the end of the developers, and/or there are insurmountable performance issues, I can get that. 
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SixOfSpades

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Re: Smoke, chimneys, and fuel use
« Reply #3 on: December 01, 2025, 05:37:38 am »

1. Soot, as a contaminant on skin/clothes/hair that will "require" cleaning, would also be a nice touch, a consequence of working in / walking through smoke.

3. Why would chimneys (or any similar construction) work in only 1 direction? The fact that Bernoulli's principle means air usually flows up a chimney does not mean that it cannot flow downward.

5. Charcoal is important as fuel, not just for providing carbon for steel reactions, but because it burns significantly hotter than unprocessed wood. Raw wood cannot burn hot enough to get iron to its working temperature--charcoal can. You'd be fine using wood in the Kitchen, and for metals with lower melting points, but iron, glass, and porcelain should all require charcoal (or magma).
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Andeerz

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Re: Smoke, chimneys, and fuel use
« Reply #4 on: December 01, 2025, 10:28:48 am »

1. Soot, as a contaminant on skin/clothes/hair that will "require" cleaning, would also be a nice touch, a consequence of working in / walking through smoke.
I like that idea...

3. Why would chimneys (or any similar construction) work in only 1 direction? The fact that Bernoulli's principle means air usually flows up a chimney does not mean that it cannot flow downward.
Good point.  They should basically constrain propagation to one axis.

5. Charcoal is important as fuel, not just for providing carbon for steel reactions, but because it burns significantly hotter than unprocessed wood. Raw wood cannot burn hot enough to get iron to its working temperature--charcoal can. You'd be fine using wood in the Kitchen, and for metals with lower melting points, but iron, glass, and porcelain should all require charcoal (or magma).

That is arguably true, but wood can burn hot enough.  It just isn't/wasn't commonly used since it doesn't form a reducing-enough environment and can burn very dirty.  And there are instances where you can even use wood for smelting iron, but in those instances, the wood essentially becomes charcoal in the smelter itself... I think it is dependent on the design of the smelter, and is something I think is too granular for this game.  Might be good to discuss further, though...  In any case, this is not a common thing IRL. 

Wood can and was historically used for glass and ceramics kilns.  It might matter for what kind of glass or ceramics, though.

Overall, charcoal and coke are used any time you need a clean-burning reducing environment, which is generally what is needed for smelting metals from oxide ores.  Interestingly, for copper sulfide ores (which were/are the major copper ores throughout history), you need to roast them in an oxidizing environment first (with wood with a lot of fresh air!) before then smelting the resulting oxides in a reducing environment to get the pure copper.  I think this goes for other metal sulfide ores, too (although for iron sulfides, practically speaking, ores that had iron sulfides weren't ever economical to smelt in large part due to how low the iron content tended to be in these ores, and that even a super tiny amount of sulfur contamination can make iron absolutely unworkable).

As for magma, I am with you.  Even though it is extremely unrealistic, magma should basically be a magic dwarfy heat source that can do anything... except for maybe food.  A magma kitchen would be sorta funny, though.
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TheMarmot

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Re: Smoke, chimneys, and fuel use
« Reply #5 on: December 02, 2025, 09:32:47 pm »

Quote
...except for maybe food.  A magma kitchen would be sorta funny, though.
While not entirely related to magma proper, Rúgbrauđ uses geothermal properties to bake it.
As an addition, I feel that this could go well with smoking food to preserve stuff like meat, but that would have to wait for some digestion system reworks
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Andeerz

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Re: Smoke, chimneys, and fuel use
« Reply #6 on: December 03, 2025, 12:12:50 am »

Quote
...except for maybe food.  A magma kitchen would be sorta funny, though.
While not entirely related to magma proper, Rúgbrauđ uses geothermal properties to bake it.
As an addition, I feel that this could go well with smoking food to preserve stuff like meat, but that would have to wait for some digestion system reworks

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DPh Kraken

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Re: Smoke, chimneys, and fuel use
« Reply #7 on: December 06, 2025, 12:44:54 am »

Ventilation and air quality feels like it'd naturally be a complement to insulation and heating/cooling.
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Thunderforge

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Re: Smoke, chimneys, and fuel use
« Reply #8 on: December 06, 2025, 10:50:57 pm »

I wonder if mine gasses could be included in this bundle?
Firedamp (Methane) floats up, combusts on contact with a fire source (or spark from tools)
Chokedamp (Carbon Dioxide) sinks to the ground, causes unconsciousness in small doses, and death after longer periods
Whitedamp (Carbon Monoxide)
Stinkdamp (Hydrogen Sulphide)
I don’t know enough about the last two to suggest how they would play out in game.

But if this was implemented I’d like to see some stuff that warns or protects us from them. Caged canaries and Knockermen would be nice.



And if furnace smoke is implemented it would be nice to have chimneys leading to the surface or up into a cavern. And then you’d need metal grates in places to stop beasties crawling in!
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slowpersun

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Re: Smoke, chimneys, and fuel use
« Reply #9 on: December 07, 2025, 05:10:16 pm »

1. Soot, as a contaminant on skin/clothes/hair that will "require" cleaning, would also be a nice touch, a consequence of working in / walking through smoke.
I like that idea...
Could be interesting to also allow for soot buildup to occasionally occur in "chimney" zones (ie, single column voids, since I'm assuming that would be the most space efficient, 3x3 minus the middle), chimney sweeping used to be a literal profession.  But might also be kind of a headache, since game doesn't have the concept of ladders, even if you can still pump water up to top of chimney to flush it out occasionally, just would require more doors to block off workshops from backflow...

3. Why would chimneys (or any similar construction) work in only 1 direction? The fact that Bernoulli's principle means air usually flows up a chimney does not mean that it cannot flow downward.
Good point.  They should basically constrain propagation to one axis.
Putting aside air as a fluid and whether that should be modeled, etc., for reasons of CPU efficiency it would be easier for certain gasses (like smoke in this instance) to never propagate downwards.  Game already does enough... I mean, we're still waiting on temp multithreading!

I wonder if mine gasses could be included in this bundle?
Firedamp (Methane) floats up, combusts on contact with a fire source (or spark from tools)
Chokedamp (Carbon Dioxide) sinks to the ground, causes unconsciousness in small doses, and death after longer periods
Whitedamp (Carbon Monoxide)
Stinkdamp (Hydrogen Sulphide)
I don’t know enough about the last two to suggest how they would play out in game.

But if this was implemented I’d like to see some stuff that warns or protects us from them. Caged canaries and Knockermen would be nice.
Yeah, crazy how many different gas combinations come up from mining!  Be interesting for when game eventually allows better explosion simulation, like gaseous explosions (one reason for game to calculate gas density).
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Andeerz

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Re: Smoke, chimneys, and fuel use
« Reply #10 on: December 07, 2025, 10:37:57 pm »

With accumulation of soot... does soot always build up IRL when it comes to "cleaner" burning reacitons (anything burning charcoal or coke)?  Wood burning furnaces for sure build up soot.  What I think smelters and stuff would build up is slag and stuff like that.  I am a bit ambivalent about chimney and furnace maintenance.  Sounds cool to me, though.   

Putting aside air as a fluid and whether that should be modeled, etc., for reasons of CPU efficiency it would be easier for certain gasses (like smoke in this instance) to never propagate downwards.  Game already does enough... I mean, we're still waiting on temp multithreading!

Yeah... I wonder how much that would affect FPS.  Allowing smoke to propagate downward would essentially be making smoke behave like miasma.  The reason I would like for smoke to propagate downward is because, combined with smoke emanating from workshops that burn stuff, it would make chimneys/rudimentary ventilation (like a single column void) beyond just at the level of the dwarf operating a furnace in an enclosed space necessary without adding anything else to the game.  And I don't see how it would add anything additional to overhead; it just means the propagation still happens but is less constrained in where it goes if it behaves how I think it does, but I don't know enough to say at all for sure.

But after thinking on this more... computation concerns aside, maybe the better thing to do would be to make smoke disappear slower and allow it to accumulate, with the smoke propagating downward as the space gets crowded (in other words, outside, a furnace is fine, but a chimney in an enclosed space that terminates within the space won't be of much benefit as smoke has nowhere to go eventually... think water but upside-down for how the smoke would accumulate).  However... this I could see tanking FPS with more than a few flows.
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