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[GavJ]

Some have ranges, a few of which are really wide:

That's actually another issue. For most of those, it's probably because they're defined by formation environment and particle size, NOT by actual mineral composition. A sandstone made out of grains of sand that happen to be pure diamond is still a sandstone, I believe, just as much as normal quartz sandstone...

So there's not really a proper answer.

Makes me lean toward "intuitively reasonable sounding BSing" possibly using something like one of the above links and just changing anything that feels weird.

[Dirst]

Some have ranges, a few of which are really wide:

That's actually another issue. For most of those, it's probably because they're defined by formation environment and particle size, NOT by actual mineral composition. A sandstone made out of grains of sand that happen to be pure diamond is still a sandstone, I believe, just as much as normal quartz sandstone...

So there's not really a proper answer.

Makes me lean toward "intuitively reasonable sounding BSing" possibly using something like one of the above links and just changing anything that feels weird.

For game purposes, "soft limestone" and "hard limestone" would probably be two different minerals, although I don't know enough geology to tell you which one is more consistent with how Toady actually uses the game's INORGANIC:LIMESTONE layers.

I see three basic steps.

1. Locate the COMPRESSIVE_FRACTURE and COMPRESSIVE_YIELD data on the layer stones, and add those into the raws of inorganic_stone_layer.txt

2. Add anything that is missing but important to fill in gaps (maybe MARL).

3. Convince Toady to incorporate the gathered stats into vanilla (this happened before with gems) and adjust mining velocity.

It may be possible to affect mining velocity with DFHack by inserting delays, but using the actual game engine would be vastly superior.

[blue sam3]

At this point, I would get some values throug POOMA: Pulled Out Of My Ass. Make up some values that make sense if you don't think about them too hard. I mean, DF already does that a lot where materials are concerned (see Iron's raws). Since we don't actually have accurate not-tensile values, somewhat inaccurate mining speed probably wouldn't be too bad.

Which material property numbers in the raws are still made up, exactly? I've got a fortnight with not much to do and a whole library full of data tables for this stuff.

[King Mir]

I think TENSILE_FRACTURE would be a better figure to use. Or just take the lowest of all the fracture types for the material.

Rocks should generally break, not deform, so fracture should always be greater than yeild. For soil layers, that's nor really true, but DF doesn't model digging in soil well.

Gems and ores could use the layer stone's properties, since especially for gems, that's the real material being picked at.

On the other end, you need a good pick, which is harder than the rock it's mining. This would mean that dwarves would need steel picks to mine igneous intrusive stone, and a lot of others. Which should be good for gameplay.

[GavJ]

You dont need picks stronger than the rock. Bashing granite with a lead mace might easily fracture it, despite a difference of several mohs steps.

As perhaps a more common example, are air or wind harder than diorite? No, yet they carve vast canyons and cleave mountains.

Hardness advantage is fine for modeling speed but not necessity.

[Putnam]

At this point, I would get some values throug POOMA: Pulled Out Of My Ass. Make up some values that make sense if you don't think about them too hard. I mean, DF already does that a lot where materials are concerned (see Iron's raws). Since we don't actually have accurate not-tensile values, somewhat inaccurate mining speed probably wouldn't be too bad.

Which material property numbers in the raws are still made up, exactly? I've got a fortnight with not much to do and a whole library full of data tables for this stuff.

Everything strength-related that isn't TENSILE_YIELD and TENSILE_STRAIN_AT_YIELD is made up based on some arbitrary multiplications of the TENSILE_YIELD value. TENSILE_YIELD itself is based on the ultimate tensile strength of the material and TENSILE_STRAIN_AT_YIELD is the ultimate tensile strength divided by the young's modulus (multiplied by 10,000 so that it's an integer). Compressive yield, for example, is just tensile yield times 3.5. All of them are like that.

[King Mir]

You dont need picks stronger than the rock. Bashing granite with a lead mace might easily fracture it, despite a difference of several mohs steps.

As perhaps a more common example, are air or wind harder than diorite? No, yet they carve vast canyons and cleave mountains.

Hardness advantage is fine for modeling speed but not necessity.

Bashing granite with lead may sort of work, but you're gonna damage the mace more than the rock. You're right, it may make sense to give a slight advantage to the pick material, but I don't think bashing granite with lead is realistic. Maybe if weapon wear were implemented.

Air and wind may help erode mountains, but those aren't the same forces at work as heaving a pick. Canyon are more often formed by the eroding effect of water.

[GavJ]

Bashing granite with lead may sort of work, but you're gonna damage the mace more than the rock. You're right, it may make sense to give a slight advantage to the pick material, but I don't think bashing granite with lead is realistic. Maybe if weapon wear were implemented.

It's extremely realistic if all you have on site is lead furniture to melt down, and a kea flew off with your only picks. Or if you want to cut something harder than anything dwarves have invented to make tools out of.

Are the dwarves going to say "Oh well, the nicest, most convenient tool isn't available, so I guess we will just sit here and starve to death" or are they going to say "Well shit, I guess we will have to make a big stupid lead hammer and spend 10x as long smashing the rocks apart until we can get something better." ? They're gonna choose the latter.

Civilizations throughout history have made huge, precision-cut monuments using tools that were softer than the rocks they were shaping. In fact, I'd go so far as to guess that cutting rocks with things softer than them has been the norm for our species in general, not the other way around.

Air and wind may help erode mountains, but those aren't the same forces at work as heaving a pick. Canyon are more often formed by the eroding effect of water.

Yeah, they don't work the same way a pick works.

...So what? If the way a pick works isn't going to get the job done... don't use a pick. use the things that DO work. This is the suggestions forum, you know. One of the changes related to mining velocity could be using and needing alternative tools that work differently or more quickly than pick technology if you don't have the right metals on hand.

A high kinetic energy hammer is one method. A more common historical one is something like getting wooden rotating poles, grinding holes into a rock with sand/grit, sticking wooden wedges in there, then soaking them with water to expand them and create tremendous pressure that splits the rock. No metals are even needed at all (though they do make this process easier too)

I think it's also often possible to use bonfires to heat some kinds of rock so they expand and crumble into useable chunks.

[King Mir]

I'm all for alternate methods of mining. Using water and wood would be cool.

I understand the sentiment to make it possible to overcome challenges with few resources, but I also think it should be suitably hard to do so. And I don't think making soft pick simply be very slow at mining is the way to do that.

I think it would also be cool to be able to create picks from large gems.

[Duck Slayer]

An added benefit of generating values based on hardness could effect a constructions durability against building destroyers or siege weapons. Such as wooden ballista bolts vs iron walls. As for building destroyers a creature composed of basalt tearing through wooden walls.

[GavJ]

An added benefit of generating values based on hardness could effect a constructions durability against building destroyers or siege weapons. Such as wooden ballista bolts vs iron walls. As for building destroyers a creature composed of basalt tearing through wooden walls.

Replace "basalt" with "obsidian" though, and reconsider: both basalt and obsidian are about equally hard, yet imagine bashing a glass club against a nice thick oaken door. Who's gonna win?
Strength just doesn't =/= hardness.

Whether or not the exceptions arising from simplifications like this (like obsidian vs. wood) would occur in high enough numbers to break a sense of realism, though, is an open question.



Also, just in general: adding mining velocity to the game, and then just letting us sort it out by putting mining speed it in the RAWs as its own parameter would pretty much address all of these issues, cause people could just try different things until we found something most people are happy with. Each modder would be free to define mining speed by whatever equation of other variables he/she sees fit, without it being inextricably tied to other things in the game.

[Dirst]

An added benefit of generating values based on hardness could effect a constructions durability against building destroyers or siege weapons. Such as wooden ballista bolts vs iron walls. As for building destroyers a creature composed of basalt tearing through wooden walls.

Replace "basalt" with "obsidian" though, and reconsider: both basalt and obsidian are about equally hard, yet imagine bashing a glass club against a nice thick oaken door. Who's gonna win?
Strength just doesn't =/= hardness.

Whether or not the exceptions arising from simplifications like this (like obsidian vs. wood) would occur in high enough numbers to break a sense of realism, though, is an open question.



Also, just in general: adding mining velocity to the game, and then just letting us sort it out by putting mining speed it in the RAWs as its own parameter would pretty much address all of these issues, cause people could just try different things until we found something most people are happy with. Each modder would be free to define mining speed by whatever equation of other variables he/she sees fit, without it being inextricably tied to other things in the game.

As a one-off feature, that's the way to go.  But if it will be part of vanilla then I think this would be best rolled in with destructible walls and cave-in physics and such, and then it makes more sense to tie things in with "real" material properties.

So you will be able to stroll through sandstone like a Horta, but the tunnel may collapse on you.

[GavJ]

Yeah, perhaps.

If you do really wish to use an algorithm, I think the best suggestion I've heard so far in the thread was the person who said "Take all the different strength-relevant numbers, and use the weakest one for each rock." Which pretty cleverly takes into account that a miner would choose whatever a rock is weakest against and exploit it, while also allowing Toady to avoid having to come up with complicated ways of calculating average strength across various methods.

(by the way, off topic-ish, but sandstone is actually quite tough on average. Sort of a mid range rock. Consider, for example, that many millstones and grinding wheels are made out of it)

[King Mir]

If you're giving rock walls real material properties, doesn't it make sense to use the same opportunity to make picks and while you're at it, axes, not be able to work on materials that are harder than them? As long as you make steal still able to mine the hardest rock.

Only trouble is, this does imply an interface change to allow more control over which pick a miner uses.

[GavJ]

If you're giving rock walls real material properties, doesn't it make sense to use the same opportunity to make picks and while you're at it, axes, not be able to work on materials that are harder than them?

No because mining doesn't require having harder tools in real life. If it did, we would be screwed as dwarves, since the huge majority of rock species in the earth's crust (e.g. biggest contributors like rhyolite, granite, schist, gneiss) are harder than steel picks.