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Difference between revisions of "v0.34:Temperature"

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(expand, rewrite, so on)
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''For temperature as it relates to choosing an embarkation site, see [[Climate]].''
 
''For temperature as it relates to choosing an embarkation site, see [[Climate]].''
 
{{buggy}}
 
{{buggy}}
 +
 
==Temperature scale==
 
==Temperature scale==
Dwarf Fortress uses its own temperature scale in most cases, often called "Degrees [[Main:Urist|Urist]]" on this wiki.
+
Temperatures in Dwarf Fortress are measured in the game's own, unnamed temperature scale, since termed "Degrees [[Main:Urist|Urist]]" by the community. Temperatures in Dwarf Fortress are stored as sixteen-bit unsigned integers, which translates into a minimum value of 0&nbsp;°U and a technical maximum of 65535&nbsp;°U (2<sup>16</sup>-1), although this is internally limited to 60000&nbsp;°U&mdash;60001&nbsp;°U is used for temperatures which have been set to <tt>NONE</tt>. Floating point values are not considered, and when they appear any decimals are either sheared off or rounded away by the game. Urists are scaled logically against the Celsius scale, so conversions are simple, if non-intuitive:
So if you see something like [HOMEOTHERM:10067], don't be amazed.
 
  
[[Magma]]'s temperature is {{ct|12000}}.
+
:<tt>[URIST]</tt> = <tt>[FAHRENHEIT]</tt> + 9968
 
+
::::&nbsp;&nbsp;&nbsp;<tt>[CELSIUS]</tt> * 9/5 + 10000
The highest possible temperature in Dwarf Fortress is {{ct|60000}} &mdash; the temperature 60001&nbsp;°U is used internally for temperatures which have been set to "NONE".
+
::::&nbsp;&nbsp;&nbsp;<tt>[KELVIN]</tt> * 9/5 + 9508.33
 
+
::::&nbsp;&nbsp;&nbsp;<tt>[RANKINE]</tt> + 9508.33
===Conversion===
 
 
 
[DF scale] = [FAHRENHEIT] + 9968
 
 
 
[DF scale] = [CELSIUS] * 9/5 + 10000
 
 
 
[DF scale] = [KELVIN] * 9/5 + 9508.33
 
 
 
[DF scale] = [RANKINE] + 9508.33
 
 
 
''(Note: Mod-makers may find this [http://www.bay12forums.com/smf/index.php?topic=80523.0 Temperature Conversion Utility] handy if they find themselves having to convert a lot of temperatures to and/or from Degrees Urist.)''
 
 
 
===Reference Chart===
 
  
 +
Some reference numbers:
 
{| {{prettytable}}
 
{| {{prettytable}}
 
|- bgcolor="#ddd"
 
|- bgcolor="#ddd"
Line 33: Line 21:
 
! Kelvin
 
! Kelvin
 
! Rankine
 
! Rankine
 
 
|-
 
|-
| Boiling Point of Water
+
| [[#Boiling point|Boiling Point of Water]]
 
| 10180
 
| 10180
 
| 212
 
| 212
Line 41: Line 28:
 
| 373.15
 
| 373.15
 
| 671.67
 
| 671.67
 
 
|-
 
|-
|Human Body Temperature
+
| [[Creature token#H|Human Body Temperature]]
| 10066.6<sup>2</sup>
+
| 10067<sup>round</sup>
 
| 98.6
 
| 98.6
 
| 37.0
 
| 37.0
 
| 310.15
 
| 310.15
 
| 558.27
 
| 558.27
 
 
|-
 
|-
 
| [[Water#Freezing point|Freezing Point of Water]]
 
| [[Water#Freezing point|Freezing Point of Water]]
Line 57: Line 42:
 
| 273.15
 
| 273.15
 
| 491.67
 
| 491.67
 
 
|-
 
|-
| Absolute Zero
+
| [[wikipedia:Absolute zero|Absolute Zero]]
| 9508.33<sup>2</sup>
+
| 9508<sup>round</sup>
 
| -459.67
 
| -459.67
 
| −273.15
 
| −273.15
 
| 0
 
| 0
 
| 0
 
| 0
 
 
|-
 
|-
| DF Scale's Zero<sup>1</sup>
+
| Zero Degrees Urist
 
| 0
 
| 0
 
| -9968
 
| -9968
| -5555.555...
+
| -5555.<span style="text-decoration:overline">5</span>
| -5282.40555...
+
| -5282.40<span style="text-decoration:overline">5</span>
 
| -9508.33
 
| -9508.33
 
|}
 
|}
  
<small>
+
Values designated with ''round'' have been rounded internally to avoid decimals: for instance, the human body temperature is technically 10066.6, but has been rounded up to {{ct|10067}} in the [[raw file|raws]]. Also interesting is the fact that temperatures in Dwarf Fortress can go ''far, far'' below absolute zero, which is physically impossible; considering Dwarf Fortress also allows [[water wheel#Perpetual motion|perpetual motion]], sometimes it's best not to ask questions. Temperature conversions are usually only useful when [[modding]], and can be annoying to do manually; luckily a simple [http://www.bay12forums.com/smf/index.php?topic=80523.0 temperature conversion utility] has been created for those who find themselves having to convert a lot of temperatures to and/or from degrees Urist often.
:<sup>1.</sup> Yes, temperatures in Dwarf Fortress can go '''far, far''' below absolute zero, which is physically impossible. Considering Dwarf Fortress also allows [[water wheel#Perpetual motion|perpetual motion]], it's best not to ask questions.
 
:<sup>2.</sup> Technically, fractional/decimal temperatures are not possible in Dwarf Fortress, as they are stored as unsigned 16-bit integers. For instance, body temp for humans in the raws is rounded to {{ct|10067}}.
 
</small>
 
 
 
  
Examples of some temperatures encountered in DF, the most important ones in bold.
+
Examples of some temperatures encountered in DF, the most important ones in bold:
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
 
|-
 
|-
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| {{ct|09850}}
 
| {{ct|09850}}
 
|-
 
|-
| Outside, [[Climate#Freezing|freezing climate]] (varies)
+
| '''<span style="border-bottom: 1px #0000CC dotted;cursor:help;" title="Below this temperature fat, present on all all organic creatures, will start to take cold damage, eventually killing them.">Lowest survivable temperature</span>'''
 +
| '''{{ct|09900}}'''
 +
|-
 +
| Outside, freezing climate (varies)
 
| {{ct|09960}}
 
| {{ct|09960}}
 
|-
 
|-
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| '''{{ct|10000}}'''
 
| '''{{ct|10000}}'''
 
|-
 
|-
| [[Nether-cap]]<sup>1</sup>
+
| <span style="border-bottom: 1px #0000CC dotted;cursor:help;" title="Nether-cap temperatures are fixed to 10000 degrees Urist, regardless of the surrounding environment.">Nether-cap</span>
 
| {{ct|10000}}
 
| {{ct|10000}}
 
|-
 
|-
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| '''{{ct|10015}}'''
 
| '''{{ct|10015}}'''
 
|-
 
|-
| Dwarf/human homeotherm
+
| [[Creature token#H|Dwarf/human homeotherm]]
 
| {{ct|10067}}
 
| {{ct|10067}}
 
|-
 
|-
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| {{ct|10080}}
 
| {{ct|10080}}
 
|-
 
|-
| Tiles next to magma ([[warm stone]])
+
| Tiles next to [[magma]] ([[warm stone]])
 
| {{ct|10075}}
 
| {{ct|10075}}
 
|-
 
|-
| Fat melts
+
| '''<span style="border-bottom: 1px #0000CC dotted;cursor:help;" title="Above this temperature fat, present on all all organic creatures, will start to melt (turning into grease), eventually killing them.">Highest survivable temperature</span>'''
| {{ct|10078}}
+
| '''{{ct|10078}}'''
 
|-
 
|-
| Water boils
+
| [[Water]] boils
 
| {{ct|10180}}
 
| {{ct|10180}}
 
|-
 
|-
| Material is fire-safe
+
| Material is [[fire-safe]]
 
| {{ct|11000}}
 
| {{ct|11000}}
 
|-
 
|-
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| {{ct|11500}}
 
| {{ct|11500}}
 
|-
 
|-
| Items on fire (max)
+
| Items on [[fire]] (max)
 
| {{ct|11640}}
 
| {{ct|11640}}
 
|-
 
|-
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| {{ct|12000}}
 
| {{ct|12000}}
 
|-
 
|-
| Creatures made of flame/fire
+
| [[Creature]]s made of flame/fire
 
| {{ct|14000}}
 
| {{ct|14000}}
 
|-
 
|-
| Dragonfire<sup>2</sup>
+
| <span style="border-bottom: 1px #0000CC dotted;cursor:help;" title="Yes, dragonfire is roughly four times hotter than the surface of the sun. Nether-cap is the only usable dragonfire-safe material in the game, due to its fixed temperature.">[[Dragon]]fire</span>
 
| {{ct|50000}}
 
| {{ct|50000}}
 
|-
 
|-
 
|}
 
|}
 
<small>
 
:<sup>1.</sup> Nethercaps have ''a fixed temperature'' of {{ct|10000}} regardless of their environment.
 
:<sup>2.</sup> Yes, dragonfire is roughly four times hotter than the surface of the sun. Nether-cap is the only ''usable'' dragonfire-safe material, due to its fixed temperature.
 
</small>
 
  
 
==Material values==
 
==Material values==

Revision as of 19:16, 12 July 2013

This article is about an older version of DF.

For temperature as it relates to choosing an embarkation site, see Climate.

Temperature scale

Temperatures in Dwarf Fortress are measured in the game's own, unnamed temperature scale, since termed "Degrees Urist" by the community. Temperatures in Dwarf Fortress are stored as sixteen-bit unsigned integers, which translates into a minimum value of 0 °U and a technical maximum of 65535 °U (216-1), although this is internally limited to 60000 °U—60001 °U is used for temperatures which have been set to NONE. Floating point values are not considered, and when they appear any decimals are either sheared off or rounded away by the game. Urists are scaled logically against the Celsius scale, so conversions are simple, if non-intuitive:

[URIST] = [FAHRENHEIT] + 9968
   [CELSIUS] * 9/5 + 10000
   [KELVIN] * 9/5 + 9508.33
   [RANKINE] + 9508.33

Some reference numbers:

Significance DF Scale Fahrenheit Celsius Kelvin Rankine
Boiling Point of Water 10180 212 100 373.15 671.67
Human Body Temperature 10067round 98.6 37.0 310.15 558.27
Freezing Point of Water 10000 32 0 273.15 491.67
Absolute Zero 9508round -459.67 −273.15 0 0
Zero Degrees Urist 0 -9968 -5555.5 -5282.405 -9508.33

Values designated with round have been rounded internally to avoid decimals: for instance, the human body temperature is technically 10066.6, but has been rounded up to 10067 °U in the raws. Also interesting is the fact that temperatures in Dwarf Fortress can go far, far below absolute zero, which is physically impossible; considering Dwarf Fortress also allows perpetual motion, sometimes it's best not to ask questions. Temperature conversions are usually only useful when modding, and can be annoying to do manually; luckily a simple temperature conversion utility has been created for those who find themselves having to convert a lot of temperatures to and/or from degrees Urist often.

Examples of some temperatures encountered in DF, the most important ones in bold:

Event / location Temperature
Alcohol freezes 09850 °U
Lowest survivable temperature 09900 °U
Outside, freezing climate (varies) 09960 °U
Underground, glacier ice 09990 °U
Water freezes 10000 °U
Nether-cap 10000 °U
Underground 10015 °U
Dwarf/human homeotherm 10067 °U
Outside, scorching climate (varies) 10080 °U
Tiles next to magma (warm stone) 10075 °U
Highest survivable temperature 10078 °U
Water boils 10180 °U
Material is fire-safe 11000 °U
Common stone melts (varies) 11500 °U
Items on fire (max) 11640 °U
Magma 12000 °U
Material is magma-safe 12000 °U
Creatures made of flame/fire 14000 °U
Dragonfire 50000 °U

Material values

Melting point

This is the temperature at which a liquid material will freeze, or a solid material will melt. In Dwarf Fortress, the melting point and freezing point coincide exactly — this is contrary to many real-life materials, which can be supercooled.

Boiling point

This is the temperature at which the material will boil or condense. Water boils at 10180 °U .

Ignition point

This is the temperature at which the material will catch fire.

Heat damage point

This is the temperature above which the material will begin to take heat damage. Burning items without a heat damage point (or with an exceptionally high one) will take damage very slowly, causing them to burn for a very long time (9 months and 16.8 days) before disappearing.

Cold damage point

This is the temperature below which the material will begin to take frost damage.

Specific heat

This determines how long it takes the material to heat up or cool down. A material with a high specific heat capacity will hold more heat and affect its surroundings more before cooling down or heating up to equilibrium.

Fixed temperature

A material's temperature can be forced to always be a certain value via the MAT_FIXED_TEMP material definition token. The only standard material which uses this is nether-cap wood, whose temperature is always at the melting point of water. If a material's temperature is fixed to between its cold damage point and its heat damage point, then items made from that material will never suffer cold/heat damage. This makes nether-caps fire-safe and magma-safe despite being a type of wood.

Due to the way fixed temperature is handled, giving a material a fixed temperature will not cause its actual temperature to change accordingly — instead, its temperature will simply be permanently locked at whatever it was previously. Removing a material's fixed temperature, however, will cause all items made of it to heat or cool until reaching equilibrium with their surroundings.

The fixed temperature of a container does affect its contents, but you can't freeze water by putting it into a bucket made from nether-cap because water will not freeze until it cools below 10000 °U .

The fixed temperature of an inorganic material has no effect on unmined walls made from that material, though boulders will take on that temperature as they are produced via mining.

Bugs

  • A calculation error causes objects in containers to maintain a 1 degree difference from the container, resulting in constant recalculation.Bug:6012 DFhack provides a tweak to stabilize the temperature of such objects.
  • Temperature calculations have a significant impact on game performance. (Temperature calculations can be disabled in the D init.txt file.)
  • When temperature calculations are disabled, dwarves will refuse to set foot in a cast obsidian tile (or other tiles previously occupied by magma).Bug:6033