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[Miles_Umbrae]

Barring any changes to the potentials of the leather industry I'd say that the best option would be if the tanner made stacks of leather based on the size of the animal(roughly: 1 squirrel and 1 rabbit equating to a one unit stack of leather).
A cow could result in a seven unit stack of leather and a dragon could result in a 175 unit stack of leather.
And making items takes different amounts of units; 2 for a pair of gloves(one for each hand), 4 units for boots, 8 for a coat .. or whatever quantities almighty Toady would consider appropriate...

[compsognathus]

Moreover one day there will be a trader's career to play, being a dragon skins trader would be great.

[voliol]

Minor note that hide size needs to be based of skin surface area, and not skin tissue volume; you don't slice the skin in half depth-wise to get twice the leather. There's not really a notion of surface area in DF bodies, but in general any volume change of the factor x should indicate a surface area change of x^2/3 .

So a fully grown dragon would give equal to (25000000/300)^2/3 = 1908 gray squirrel skins, as opposed to 25000000/300 = 83333 if it was directly based off volume. A cat would give 6 squirrel skins, a dog 21, and a cow 158.

[thefriendlyhacker]

Minor note that hide size needs to be based of skin surface area, and not skin tissue volume; you don't slice the skin in half depth-wise to get twice the leather. There's not really a notion of surface area in DF bodies, but in general any volume change of the factor x should indicate a surface area change of x^2/3 .

So a fully grown dragon would give equal to (25000000/300)^2/3 = 1908 gray squirrel skins, as opposed to 25000000/300 = 83333 if it was directly based off volume. A cat would give 6 squirrel skins, a dog 21, and a cow 158.

The problem is deeper than that, though. In real life, you get relatively less hide off larger animals for their body mass because their skin is thicker, and this results in thicker leather rather than more of it.  In Dwarf Fortress, there is no concept of different materials or material sources producing items of different thickness.  At the moment, vertibrate skin (or equivalent) thickness is fixed at about 1/56th of the creature's total tissue by depth, depending on body part. As an illustrative estimate (treating creatures as simple spheres), a dog would have a skin thickness of 5mm, which is on the upper end of the real life figure (0.5-5mm).  On the other hand, a dragon would have a skin thickness of 5cm.  Since a real life elephant has a skin thickness of about half that, these numbers are roughly right, but if you want to capture this correctly then you have to have hides created from butchered creatures carry data describing the thickness of the creature body part they came from (factoring in that particular creature's size, as varied by age and size modifiers), and this property has to be conserved and factored in from the butchered hides all the way to the final products (bags, armor etc).  Do that, and the whole surface area vs size thing will solve itself.

[voliol]

Minor note that hide size needs to be based of skin surface area, and not skin tissue volume; you don't slice the skin in half depth-wise to get twice the leather. There's not really a notion of surface area in DF bodies, but in general any volume change of the factor x should indicate a surface area change of x^2/3 .

So a fully grown dragon would give equal to (25000000/300)^2/3 = 1908 gray squirrel skins, as opposed to 25000000/300 = 83333 if it was directly based off volume. A cat would give 6 squirrel skins, a dog 21, and a cow 158.

The problem is deeper than that, though. In real life, you get relatively less hide off larger animals for their body mass because their skin is thicker, and this results in thicker leather rather than more of it.

That's more or less what I tried to say, though I might have skipped a few steps of math. Basically, it is what happens to any 2-dimensional surface of a 3-dimensional object when you scale the 3-dimensional object directly. As the creature sizes are defined as measurements of volume (cm³)(3D), comparing two of them gives you a factor that can be used in conjunction with one of them to scale it into the other. This is then exponentiated by 1/3 (cube root) to get how much the object is scaled in 1D, and then exponentiated by 2 (squaring) to get that factor for 2D. If we call the 3D scaling factor x we get (x^1/3)² = x^1/3*2 = x^2/3. This holds for any 2D surface of a 3D object, be it a cube, sphere, or Dwarf Fortress creature.

Of course, there should also be some notion of leather thickness, either like SixOfSpades suggested (and a few mods have already implemented) with different "leather thickness/toughness levels" specified for each animal, or it could be pulled directly from the geometry of the creatures. A combination of the two could be possible as well of course, so giant rhinoceroses would have thicker leather than normal ones, despite the two of them both having "tough skin".

[GoblinCookie]

Minor note that hide size needs to be based of skin surface area, and not skin tissue volume; you don't slice the skin in half depth-wise to get twice the leather. There's not really a notion of surface area in DF bodies, but in general any volume change of the factor x should indicate a surface area change of x^2/3 .

So a fully grown dragon would give equal to (25000000/300)^2/3 = 1908 gray squirrel skins, as opposed to 25000000/300 = 83333 if it was directly based off volume. A cat would give 6 squirrel skins, a dog 21, and a cow 158.

The problem is deeper than that, though. In real life, you get relatively less hide off larger animals for their body mass because their skin is thicker, and this results in thicker leather rather than more of it.  In Dwarf Fortress, there is no concept of different materials or material sources producing items of different thickness.  At the moment, vertibrate skin (or equivalent) thickness is fixed at about 1/56th of the creature's total tissue by depth, depending on body part. As an illustrative estimate (treating creatures as simple spheres), a dog would have a skin thickness of 5mm, which is on the upper end of the real life figure (0.5-5mm).  On the other hand, a dragon would have a skin thickness of 5cm.  Since a real life elephant has a skin thickness of about half that, these numbers are roughly right, but if you want to capture this correctly then you have to have hides created from butchered creatures carry data describing the thickness of the creature body part they came from (factoring in that particular creature's size, as varied by age and size modifiers), and this property has to be conserved and factored in from the butchered hides all the way to the final products (bags, armor etc).  Do that, and the whole surface area vs size thing will solve itself.

Surely you get both more leather and thicker leather from larger animals?  But because of the dimensions the amount of extra leather does not increase proportionally to the total bulk of the creature?

[warwizard]

Raising this thread from the dead, I'm the OP. It's been 5 1/2 years now and the Steam port has been done, so can we have this issue considered for development?

[Ziusudra]

Already has been added:

multiple leather items per skin based on size

[warwizard]

Thanks.

[Urist Mchateselves]

Scales could be used (see crocodiles), but not chitin, apart if fantasy is involved.

There's plenty of giant bugs in DF, so why not use chitin as leather? Insect chitin isn't like plastic or ceramics like it's sometimes portrayed, but well, leathery. Chitin of a bear-sized grasshopper could be used as tough leather.

You learn something new every day. Subterranean animal people dressed in giant cave spider leather armor would be pretty cool.