Editing RNG

{{Speculation}}
{{Community}}
{{UpdateMe|If you see any wrong statements, please feel free to edit or write in the comment section what is incorrect.}}
{{Infobox
| Box title = Random number generator
| image = RNGChangesFixed.png
| caption = Coin flip test results from a more "random" RNG<ref name="steve_forum">{{Ref|title=Rng Algorithm Bugs/changes|first=Steve|last=Sinclair|year=2013|month=11|day=5|publisher=Warframe Forums|url=https://forums.warframe.com/topic/128402-rng-algorithm-bugschanges/|access-date=2022-07-26|archive-url=https://web.archive.org/web/20220726045844/https://forums.warframe.com/topic/128402-rng-algorithm-bugschanges/|archive-date=2022-07-26}}</ref>
}}
'''Random number generation''' (or '''RNG''') is the generation of a sequence of numbers that cannot be reasonably predicted better than by a [[wikipedia:Randomness|random chance]], usually through a [[wikipedia:Random number generation|random-number generator]].<ref>https://en.wikipedia.org/wiki/Random_number_generation</ref> RNG is an essential feature in [[WARFRAME]] as it is involved in many components of the game such as graphics<ref name="steve_forum" />, weapon mechanics such as [[Critical Hit]]s, generation of mission [[Tile Sets]], and more. These game mechanics use varying degrees of randomness for performance purposes, with more rigorous methods taking longer to generate more "random" numbers as a tradeoff to computational speed.<ref name="steve_forum" />

Most importantly, RNG is essential to the core gameplay loop with obtaining in-game items. The drop chance of an item can determine its trade value and influence a player's means of obtaining it such as farming, [[trading]], or purchasing with in-game or real-world currency. This article will explain some details on RNG in relation to WARFRAME's [[Drop Tables]] and should only be used for educational purposes since these mechanics may not apply to WARFRAME in its current state.

==Generating Random Numbers==
<gallery>
RNGChangesBugged.png|Poor RNG, very predictable but fastest performance; generation of a binary result (false/true, 0/1, coin flip) over multiple trials<ref name="steve_forum" />
RNGChangesFast.png|Better RNG, but still a discernible cyclical pattern<ref name="steve_forum" />
RNGChangesFixed.png|Best RNG, still deterministic but harder to discern pattern from human perspective; true RNG would have each result be independently drawn and not depend on previous results<ref name="steve_forum" />
</gallery>
As in many video games<ref>See [[#External Links]] for some examples of random number generators in other games</ref>, random numbers are not generated [[wikipedia:Nondeterministic_algorithm|non-deterministically]] since they use computational algorithms that give the ''appearance'' of a random sequence, also known as [[wikipedia:Pseudorandom number generator|pseudorandom number generators]]. To the human eye, these numbers may look random, but they are actually from [[wikipedia:Deterministic_algorithm|deterministic algorithms]]; under certain conditions and parameters, the algorithm will always return the same 'random' number. Throughout this article, the term "RNG" will refer to pseudorandom number generators.

===RNG Fairness===
A RNG is considered 'fair' when the random numbers it outputs correspond or results to the expected drop chances over an '''extended period of time''' (e.g. hundreds of runs) or '''throughout a [[wikipedia:Statistical_population|population]]''' (in this case, WARFRAME's playerbase). In other words, the random numbers the RNG outputs follow a [[wikipedia:Continuous uniform distribution|uniform distribution]] over an extended period of time.

Say one is trying to get {{WF|Gara Prime}}'s main blueprint from a Radiant {{Relic|Axi G6}}. According to the [[Drop Tables|official drop table repository]], the blueprint has a 10% chance of dropping so a single player would expect to get the blueprint after opening an average of {{MathText|1 / 10% &#61; 10}} Radiant {{Relic|Axi G6}}. In the long term, say after opening 1,000 Radiant {{Relic|Axi G6}}, the player would expect to get an average of 100 Gara Prime blueprints. These expected number of runs/drop table rolls or expected number of rewards over a number of runs/drop table rolls would be accurate if the written drop chances actually reflected on actual drop chances calculated by the in-game RNG. With a large [[wikipedia:Sample_size_determination|sample size]], if any deviation from these values is not within [[wikipedia:Errors and residuals|statistical error]], then one could say that the 10% drop chance is "inaccurate".

Note that one cannot directly conclude that the drop tables are wrong or accurate from statistical methods (e.g. comparison of expected and observed count data using [[wikipedia:Chi-squared test|Chi-squared test]]), just the observations are statistically different from the expected drop rates. Use statistical analysis as a starting point for more research to be done (more sampling or rigorous tests) or to scrutinize drop tables' accuracy. There may be one or several reasons why your experience does not match expected rates:
*The displayed drop chances are inaccurate from in-game chances.
**The in-game drop sources are incorrect and outdated (e.g. in the [[Codex]] or [[Chat]] item link descriptions)
**The official drop tables are incorrect and outdated (i.e. https://www.warframe.com/droptables)
**The wiki's manually updated drop tables are incorrect and outdated (e.g. [[Module:DropTables/data]] or [[Module:Void/data]])
*Players are farming the wrong mission/enemy or rolling the wrong drop table (like in the case of [[Disruption]] where squad performance affects whether or not a rotation reward pulls from A, B, or C drop table).
**There may be rare instances where a specific reward is missing from drop tables.<ref>{{Ref|title=The New War: Hotfix 31.0.11|first=Rebecca|last=Ford|year=2022|month=1|day=25|publisher=Warframe Forums|url=https://forums.warframe.com/topic/1298151-the-new-war-hotfix-31011/|access-date=2022-08-17|archive-url=https://web.archive.org/web/20220125200711/https://forums.warframe.com/topic/1298151-the-new-war-hotfix-31011/|archive-date=2022-01-25|extra="Vaulted the Neo P2 Relic and replaced it with the Neo P4 Relic in the drop tables. The Neo P2 Relic was missed being Vaulted with Harrow Prime’s release."}}</ref><ref>{{Ref|title=Khora Prime: Hotfix 31.7.2|first=Megan|last=Everett|year=2022|month=8|day=17|publisher=Warframe Forums|url=https://forums.warframe.com/topic/1319647-khora-prime-hotfix-3172/|access-date=2022-08-17|archive-url=https://web.archive.org/web/20220817194850/https://forums.warframe.com/topic/1319647-khora-prime-hotfix-3172/|archive-date=2022-08-17|extra="Replaced the duplicate Meso H2 Relic dropping in Tier 2 Defense with the correct Meso H3 Relic."}}</ref><ref>{{Ref|title=Veilbreaker: Revenant Prime: Hotfix 32.0.11|first=Megan|last=Everett|year=2022|month=10|day=6|url=https://forums.warframe.com/topic/1327157-veilbreaker-revenant-prime-hotfix-32011/|access-date=2022-10-17|archive-url=https://web.archive.org/web/20221017180912/https://forums.warframe.com/topic/1327157-veilbreaker-revenant-prime-hotfix-32011/|archive-date=2022-10-17|extra="Swapped the unintentional duplicate Lith H5 Relic in the Void drop tables with a Lith P6."}}</ref>
*There is a bug/issue with the game's RNG.<ref>"Glen (our Tech Director) identified and fixed a serious distribution flaw with random number generation (RNG) in Warframe. While enemy drops were not seriously affected, a truncation in the random 'seed' within the mission reward script could result in a terrible chain of bad luck. While some players may have benefited from this (a chain of good luck) the distribution was terrible." - {{ver|10.6.2}} patch notes</ref><ref>{{ver|29.5.7}} fixed a short-lived issue on Ayatan Amber Star drop rates: "Fixed Ayatan Amber Stars dropping far less frequently than before Deimos Arcana."</ref>
*There is an external factor that is not accounted for that is manipulating drop chances/RNG (e.g. having a squad member with a [[Mod Drop Chance Booster]] active).
*The possibility that a player is astronomically (un)lucky with their drops.
**If the RNG is truly fair with no manipulation, we would expect a (very) small portion of the player base to experience the extremes since every possible sequence of values is equally likely to appear.<ref name="random.org_analysis">"So, why is it hard to test whether a given sequence of numbers is random? The reason is that if your random number generator (or your die) is good, each possible sequence of values (or die rolls) is equally likely to appear. This means that a good random number generator will also produce sequences that look nonrandom to the human eye (e.g., a series of ten rolls of six on our die) and which also fail any statistical tests that we might expose it to. If you flip enough coins, you will get sequences of coin flips that seen in isolation from the rest of the sequence don't look random at all." - https://www.random.org/analysis/</ref>
***Say 30,000 players have farmed and built the {{WF|Rhino}} Warframe. Knowing that the Rhino Neuroptics, Chassis, and Systems blueprints have a 38.72%, 38.72%, and 22.56% chance of dropping<ref>From official [[Drop Tables]], retrieved 2022-02-14</ref>, we would say that there is a {{Math|0.2256 ^ 5|mt=y|p=y}} probability for a player to get five Systems blueprints in a row (similar to rolling the same number on a 5-sided die five times in a row). Therefore, we would expect around 18 players out of that 30k to have this (un)lucky experience (since {{Math|30000 * (0.2256 ^ 5)|mt=y}}).
**Randomness is not necessarily uniform, especially in small sample sizes; with a large enough sample size, there is clustering in any random distribution and players may experience either end of the drop experience (extremely 'lucky' or 'unlucky' with their reward drops). For example, a binary random number generator may produce the following sequence: <code>"101011101110101001001001101110000101101<u>'''00000000'''</u>11010000001111010011010001100001011010111110101111010"</code>. The value 0 is rolled eight times in a row which may seem nonrandom to humans since our cognitive understanding of probability tends to view randomness as a uniform process, where we immediately expect an equal number of 0's and 1's to be rolled between any given period of time.{{Cite}}
*Player's [[wikipedia:Confirmation bias|confirmation bias]] through a relatively small sample size of drop experiences to support sweeping claims that drop tables are wrong. Player's method of sampling may be subjected to [[wikipedia:Sampling bias|sampling bias]].
**By the [[wikipedia:Law of large numbers|law of large numbers theorem]], the average of the results should be close to expected value the more trials are done. In the context of WARFRAME, the more times a particular drop table is rolled, the closer that the resultant number of drops should match the expected number of drops calculated from drop chances.

===Seeding RNG===
{{Speculation}}
It is unknown how WARFRAME generates the seed(s) for the random number generators that are used to determine drops from drop tables.

<!-- rand() may be used for some more rudimentary stuff. Drop tables should use more rigorous methods to generate seeding to prevent abuse-->
For seeding rudimentary random number generators, WARFRAME may use a machine-based random function (<code>rand()</code> in [[wikipedia:C++|C++]]) to produce returns a pseudo-random number in the range between <code>0</code> and <code>RAND_MAX</code>.<ref name="c++_rand">https://www.cplusplus.com/reference/cstdlib/rand/</ref>

Based on [[EE.log]], a modified <code>[https://www.cplusplus.com/reference/cstdlib/srand/ srand()]</code> is intialized with a unique, non-repeating 64-bit value between <code>−(2^63)</code> to <code>2^63 − 1</code> (e.g. do not expect 1 or 2,222,222,222,222,222,222 to be the seed of the RNG).

Sample RNG seeds:
*<code>-7741523468968126435</code>
*<code>2541993907054812653</code>
*<code>-7134035214884351693</code>
*<code>-3354772158446415432</code>
*<code>9209242484211992089</code>
*<code>-451729703806461350</code>
*<code>1984020437910075226</code>

===Weighted RNG===
In a weighted random number generators, certain values will tend to appear more than others due to a bias (or [[wikipedia:Weight function|weights]]) associated with those values. See [[#Rarity Weights]] and [[#Bias]] on how WARFRAME uses weighted values in their drop tables to make some rewards drop more frequently than others and vice versa.

It is also known that randomized innate bonuses to [[:Category:Kuva Lich Weapons|Kuva]] and [[:Category:Tenet Weapons|Tenet]] weapons are weighted towards the lower percentages.<ref name="lich_bonus">[https://www.reddit.com/r/Warframe/comments/dz0tze/kuva_lich_data_weapon_drop_rates_elemental_bonus/ Kuva Lich Data Weapon Drop Rates, Elemental Bonus Chance, Birth Places, Names] ([https://archive.org/details/screenshot-2022-01-24-at-16-06-50-kuva-lich-data-weapon-drop-rates-elemental-bon Archived])</ref> [[Warframes]] chosen for [[Helminth]] Invigorations are also subjected to weighted values.<ref>{{Ref|title=Helminth weekly Invigorations are weighted|author=Voltage_WF|year=2021|month=7|day=8|publisher=Reddit|url=https://www.reddit.com/r/Warframe/comments/ogg9pu/helminth_weekly_invigorations_are_weighted/|access-date=2022-07-12|archive-url=https://web.archive.org/web/20220712145719/https://www.reddit.com/r/Warframe/comments/ogg9pu/helminth_weekly_invigorations_are_weighted/|archive-date=2022-07-12}}</ref>

===Linear Congruential Generator===
One of the algorithms WARFRAME uses for generating pseudo-random numbers is [https://web.archive.org/web/20180621131253/http://www.eternallyconfuzzled.com:80/tuts/algorithms/jsw_tut_rand.aspx Donald Knuth's version] of a [[wikipedia:Linear_congruential_generator|Linear Congruential Generator (LCG)]], scaling off '''[[#Rarity Weights|rarity weights]]''' that influence the drop chances of items in '''<code>/Lotus/Types/DropTables</code>''' (enemy drop tables) and '''<code>/Lotus/Types/Game/MissionDecks</code>''' (mission drop tables).<ref name="void_blog">Devove, FineNerds, & VoiD_Glitch. (n.d.). ''WARFRAME - Rarity Weights and "Random" Number Generation''. Retrieved from July 13, 2018 on VoiD_Glitch's Github (since takened down) [[RNG/Archived|Archived]] from the original on December 21, 2018.</ref><ref name="navarro">Navarro, J. (2016). ''Random Number Generation in Warframe''. Navarroj.me. https://navarroj.me/WarframeRNG.html [https://web.archive.org/web/20210710192743/https://navarroj.me/WarframeRNG.html Archived] from the original on July 10, 2021.</ref>

Note that the following LCG formula only applies to endless missions that involve getting rewards over time, such as [[Defense]] and [[Survival]].

:<math>X_n = (a(X_{n-1}) + c) \mod m</math> 

Where <math>X</math> is the [[wikipedia:sequence|sequence]] of pseudorandom values, and
:<math> m,\, 0 < m </math> — "modulus", WARFRAME uses 1
:<math> a,\, 0 < a < m</math> — "multiplier"
:<math> c,\, 0 \le c < m</math> — "increment", randomly chosen based on seed value
:<math> X_0,\, 0 \le X_0 < m</math> — seed value for RNG
:<math> n,\, n > 0</math> — current iteration or reward rotation number, an integer

This type of RNG is cyclical in nature, meaning that after a certain number of iterations or period, the generator will return the same sequence of values, subsquently completing a "cycle".

For example, a LCG with a short period can be created using the following parameters<ref name="gdc_2015">{{Ref|title=Math for Game Programmers: Parallel Random Number Generation @ 7:25|first=Manny|last=Ko|year=2015|month=3|publisher=GDC|url=https://youtu.be/qO8FAQvlgX0?t=445|access-date=2022-07-26|archive-url=https://web.archive.org/web/20220209224711/https://www.youtube.com/watch?v=qO8FAQvlgX0|archive-date=2022-02-09}}</ref>: <code>m = 8, a = 3, c = 4, seed = 2147483647</code>
The resultant sequence of numbers will look like:

<pre>
1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, ...
</pre>

<hr />
In the cases of missions like [[Capture]] and [[Exterminate]] where players earn a reward upon mission completion, they simply use the process explained in [[#Reward Seeds]] and do not use LCG for random number generation.

==Rarity Weights==
WARFRAME uses four [[rarity]] weights in its RNG algorithm(s). These weights are the same across '''<code>DropTables</code>''' and '''<code>MissionDecks</code>''', with the exception of [https://n8k6e2y6.ssl.hwcdn.net/repos/hnfvc0o3jnfvc873njb03enrf56.html#sortieRewards /Lotus/Types/Game/MissionDecks/SortieRewards], which uses '''<code>FixedWeights</code>''' that are manually assigned by the [[Digital Extremes|developers]].<ref name="void_blog" /><ref name="navarro" />

{| class="wikitable" position="center" width="400px"
|+'''<code>DropTables</code>''' and '''<code>MissionDecks</code>'''
|-
!Rarity !! Weight !! Percentage
|-
|Common || 0.755 || 75.50%
|-
|Uncommon || 0.22 || 22.00%
|-
|Rare || 0.02 || 2.00%
|-
|Legendary || 0.005 || 0.50%
|-
|colspan="3" | 0.755 + 0.22 + 0.02 + 0.005 = 1
|}
<!-- Purely speculative based on rarity classification of in-game Sortie table; in reality, these weights may be hard-coded per item OR
could use a separate weighting system with biases applied
{| class="wikitable" position="center" width="400px"
|+ [[Sortie]] (speculative '''<code>FixedWeights</code>''')
|-
!Rarity !! Weight !! Percentage
|-
|Common || 0.5591 || 55.91%
|-
|Uncommon || 0.3391 || 33.91%
|-
|Rare || 0.1 || 10.00%
|-
|Legendary || 0.0018 || 0.18%
|-
|colspan="3" | 0.5591 + 0.3391 + 0.1 + 0.0018 = 1
|}
-->

==Normalization==
[[wikipedia:Normalization (statistics)|Normalization]] occurs when one or more of the rarity weights are not present in a '''<code>DropTable</code>''' or '''<code>MissionDeck</code>'''. It refers to the division of constants that are added up so values fall between zero (0) and one (1) within different data sets.<ref name="void_blog" />

===Example Normalization Procedure===
<pre>
Say a drop table has 1 Common, 1 Uncommon, 1 Rare, and 0 Legendary drops.
Normalize the rarity weightings by dividing by the sum of present rarity weightings
in drop table to ensure weightings add up to 100% exactly.

  Common: 0.755 / (0.755 + 0.22 + 0.02) = 0.758793969849246 = 75.8793969849246% ≈ 75.88%
Uncommon: 0.22 / (0.755 + 0.22 + 0.02)  = 0.221105527638191 = 22.1105527638191% ≈ 22.11%
    Rare: 0.02 / (0.755 + 0.22 + 0.02)  = 0.020100502512562 = 2.01005025125628% ≈ 2.01%

0.758793969849246 + 0.221105527638191 + 0.201005025125628 = 1 = 100%
</pre>

===Normalization Visualization===
The two bar visuals below will demonstrate rarity weightings before and after normalization in a situation where a drop table has only uncommon and rare rarity weightings assigned to its item drops. Notice how the normalized weightings take up the entire range of all possible values between 0 inclusive and 1 exclusive while maintaining the same relative size between the different rarity weight classes (i.e. the same 11:1 ratio is maintained between uncommon and rare drops before and after normalization).

{| width=100% style="text-align:center;"
|+ Bar visualization of initial weights
|-
| colspan=1 align="left" | ▾ 0
| colspan=2 align="right" | 1 ▾
|-
| style="background:#d1d0d1; color:black;" width=22.00% | 22.00% Uncommon Drop
| style="background:#ece175; color:black;" width=2.00% | 2.00% Rare Drop
| style="background:#000000; color:white;" width=76% | 76% No Item Drop
|-
|}
<hr />
{| width=100% style="text-align:center;"
|+ Bar visualization of normalized weights
|-
| colspan=1 align="left" | ▾ 0
| colspan=1 align="right" | 1 ▾
|-
| style="background:#d1d0d1; color:black;" width=91.67% | 91.6667% Uncommon Drop
| style="background:#ece175; color:black;" width=8.33% | 8.3333% Rare Drop
|-
|}

===Different Rarity Weightings after Normalization===
{| class="emodtable" position="center" width=100%
|-
! Present Weights !! Rarity !! Normalized Weight !! Percentage
|-
| rowspan=5 | All || Common || 0.755 || 75.50%
|-
| Uncommon || 0.22 || 22.00%
|-
| Rare || 0.02 || 2.00%
|-
| Legendary || 0.005 || 0.50%
|-
! colspan=3 | 0.755 + 0.22 + 0.02 + 0.005 = 1
|-
| rowspan=5 | Common, Uncommon, and Rare || Common || {{Math|0.755 / (0.755 + 0.22 + 0.02)|round=0.0000000001|t=y}} || 75.88%
|-
| Uncommon || {{Math|0.22 / (0.755 + 0.22 + 0.02)|round=0.0000000001|t=y}} || 22.11%
|-
| Rare || {{Math|0.02 / (0.755 + 0.22 + 0.02)|round=0.0000000001|t=y}} || 2.01%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.7588 + 0.2211 + 0.0201 + 0.00 = 1
|-
| rowspan=5 | Common, Uncommon, and Legendary || Common || {{Math|0.755 / (0.755 + 0.22 + 0.005)|round=0.0000000001|t=y}} || 77.04%
|-
| Uncommon || {{Math|0.22 / (0.755 + 0.22 + 0.005)|round=0.0000000001|t=y}} || 22.45%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || {{Math|0.005 / (0.755 + 0.22 + 0.005)|round=0.0000000001|t=y}} || 0.51%
|-
! colspan=3 | 0.7704 + 0.2245 + 0.00 + 0.0051 = 1
|-
| rowspan=5 | Common, Rare, and Legendary || Common || {{Math|0.755 / (0.755 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 96.79%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || {{Math|0.02 / (0.755 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 2.56%
|-
| Legendary || {{Math|0.005 / (0.755 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 0.64%
|-
! colspan=3 | 0.96795 + 0.00 + 0.02564 + 0.00641 = 1
|-
| rowspan=5 | Uncommon, Rare, and Legendary || Common || 0.00 || 0.00%
|-
| Uncommon || {{Math|0.22 / (0.22 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 89.80%
|-
| Rare || {{Math|0.02 / (0.22 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 8.16%
|-
| Legendary || {{Math|0.005 / (0.22 + 0.02 + 0.005)|round=0.0000000001|t=y}} || 2.04%
|-
! colspan=3 | 0.00 + 0.8980 + 0.0816 + 0.0204 = 1
|-
| rowspan=5 | Common and Uncommon || Common || {{Math|0.755 / (0.755 + 0.22)|round=0.0000000001|t=y}} || 77.44%
|-
| Uncommon || {{Math|0.22 / (0.755 + 0.22)|round=0.0000000001|t=y}} || 22.56%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.7744 + 0.2256 + 0.00 + 0.00 = 1
|-
| rowspan=5 | Common and Rare || Common || {{Math|0.755 / (0.755 + 0.02)|round=0.0000000001|t=y}} || 97.42%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || {{Math|0.02 / (0.755 + 0.02)|round=0.0000000001|t=y}} || 2.58%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.9742 + 0.00 + 0.0258 + 0.00 = 1
|-
| rowspan=5 | Common and Legendary || Common || {{Math|0.755 / (0.755 + 0.005)|round=0.0000000001|t=y}} || 99.34%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || {{Math|0.005 / (0.755 + 0.005)|round=0.0000000001|t=y}} || 0.66%
|-
! colspan=3 | 0.9934 + 0.00 + 0.00 + 0.0066 = 1
|-
| rowspan=5 | Uncommon and Rare || Common || 0.00 || 0.00%
|-
| Uncommon || {{Math|0.22 / (0.22 + 0.02)|round=0.0000000001|t=y}} || 91.67%
|-
| Rare || {{Math|0.02 / (0.22 + 0.02)|round=0.0000000001|t=y}} || 8.33%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.00 + 0.9167 + 0.0833 + 0.00 = 1
|-
| rowspan=5 | Uncommon and Legendary || Common || 0.00 || 0.00%
|-
| Uncommon || {{Math|0.22 / (0.22 + 0.005)|round=0.0000000001|t=y}} || 97.78%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || {{Math|0.005 / (0.22 + 0.005)|round=0.0000000001|t=y}} || 2.22%
|-
! colspan=3 | 0.00 + 0.9778 + 0.00 + 0.0222 = 1
|-
| rowspan=5 | Rare and Legendary || Common || 0.00 || 0.00%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || {{Math|0.02 / (0.02 + 0.005)|round=0.0000000001|t=y}} || 80%
|-
| Legendary || {{Math|0.005 / (0.02 + 0.005)|round=0.0000000001|t=y}} || 20%
|-
! colspan=3 | 0.00 + 0.00 + 0.80 + 0.20 = 1
|-
| rowspan=5 | Common only || Common || 1.00 || 100%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 1.00 + 0.00 + 0.00 + 0.00 = 1
|-
| rowspan=5 | Uncommon only || Common || 0.00 || 0.00%
|-
| Uncommon || 1.00 || 100%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.00 + 1.00 + 0.00 + 0.00 = 1
|-
| rowspan=5 | Rare only || Common || 0.00 || 0.00%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || 1.00 || 100%
|-
| Legendary || 0.00 || 0.00%
|-
! colspan=3 | 0.00 + 0.00 + 1.00 + 0.00 = 1
|-
| rowspan=5 | Legendary only || Common || 0.00 || 0.00%
|-
| Uncommon || 0.00 || 0.00%
|-
| Rare || 0.00 || 0.00%
|-
| Legendary || 1.00 || 100%
|-
! colspan=3 | 0.00 + 0.00 + 0.00 + 1.00 = 1
|-
|}

===Example of Other Rarity Weightings===
[[File:T1IsoVaultRewards.jpg|thumb|right|500px|In-game representation of item rarity in bounty drop tables; notice how items are ordered in ascending order by alphanumerical sorting and not by their drop chances]]
{| class="wikitable"
|+ Evidence of different rarity weightings used in Isolation Vault Bounties<ref name="drop_table" />
|-
| colspan=3 | Level 30 - 40 [[Isolation Vault]]
|-
| colspan=3 | Rotation A
|-
| || colspan=2 | Final Stage
|-
| || Residual Boils || Uncommon (25.00%)
|-
| || Necramech Redirection || Uncommon (12.50%)
|-
| || 2X Orokin Orientation Matrix || Rare (6.25%)
|-
| || Meso P4 Relic || Rare (6.25%)
|-
| || Residual Shock || Uncommon (15.00%)
|-
| || Necramech Steel Fiber || Rare (7.50%)
|-
| || 2X Orokin Ballistics Matrix || Rare (3.75%)
|-
| || Neo D3 Relic || Ultra Rare (1.88%)
|-
| || Neo T4 Relic || Ultra Rare (1.88%)
|-
| || Theorem Contagion || Uncommon (10.00%)
|-
| || Necramech Thrusters || Rare (4.00%)
|-
| || Damaged Necramech Weapon Barrel || Rare (3.00%)
|-
| || 3X Scintillant || Rare (2.00%)
|-
| || 2X Orokin Animus Matrix || Legendary (0.50%)
|-
| || Axi O5 Relic || Legendary (0.50%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization using in-game representation of rarity weightings<ref>See [[:File:T1IsoVaultRewards.jpg]]</ref>
|-
| colspan=10 align="left" | ▾ 0
| colspan=5 align="right" | 1 ▾
|-
| style="background:white; color:black;" width=25% | Residual Boils
| style="background:lightgray; color:black;" width=12.5% | Necramech Redirection
| style="background:white; color:black;" width=6.25% | <!--Meso P4 Relic-->
| style="background:lightgray; color:black;" width=6.25% | <!--2X Orokin Orientation Matrix-->

| style="background:white; color:black;" width=15% | Residual Shock
| style="background:lightgray; color:black;" width=7.5% | <!--Necramech Steel Fiber-->
| style="background:white; color:black;" width=3.75% | <!--2X Orokin Ballistics Matrix-->
| style="background:lightgray; color:black;" width=1.88% | <!--Neo D3 Relic-->
| style="background:white; color:black;" width=1.88% | <!--Neo T4 Relic-->

| style="background:lightgray; color:black;" width=10% | Theorem Contagion
| style="background:white; color:black;" width=4% | <!--Necramech Thrusters-->
| style="background:lightgray; color:black;" width=3% | <!--Damaged Necramech Weapon Barrel-->
| style="background:white; color:black;" width=2% | <!--3X Scintillant-->
| style="background:lightgray; color:black;" width=0.5% | <!--2X Orokin Animus Matrix-->
| style="background:white; color:black;" width=0.5% | <!--Axi O5 Relic-->
|-
| style="background:#bd9177;" colspan=4 | &nbsp;
| style="background:#d1d0d1;" colspan=5 |
| style="background:#ece175;" colspan=6 |
|-
| colspan=4 | Common (25% + 12.5% + 6.25% + 6.25% = 50%)
| colspan=5 | Uncommon (15% + 7.5% + 3.75% + 1.88% + 1.88% = 30.01%)
| colspan=6 | Rare (10% + 4% + 3% + 2% + 0.5% + 0.5% = 20%)
|-
|}
*Note that official drop table repository rounds values to nearest two decimal places.

==Rarity Classification==
{{Transclude|Drop Tables#Rarity Classification}}

Note that an item's drop chance's rarity weighting may not be the same as the item's rarity classification. For example, in the drop table shown in [[#Example of No Bias]], {{M|Revenge}} uses the Common rarity weighting in calculating its drop chance, but its resultant drop chance falls between 10.00% - 33.32% so the drop table repository refers to it as an "Uncommon" reward.

=="Manipulating" RNG==
WARFRAME offers some in-game ways to increase player's chances of getting certain rewards. These include:
*Using {{Resource|Void Traces}} to upgrade [[Void Relic]]s' quality:
{| class="article-table"
! Quality
! Traces !! Common !! Uncommon !! Rare
|-
|Intact (default)
| 0 || 76% (25.33% each) || 22% (11% each) || 2%
|-
| Exceptional
| 25 || 70% (23.33% each) || 26% (13% each) || 4%
|-
| Flawless
| 50 || 60% (20% each) || 34% (17% each) || 6%
|-
| Radiant
| 100 || 50% (16.67% each) || 40% (20% each) || 10%
|}
*Having an active [[Resource Drop Chance Booster]] to double the chance at which resource drop tables are rolled.
*Having an active [[Mod Drop Chance Booster]] to double the chance at which mod drop tables are rolled.
*Having an active [[True Master's Font]] Resource Drop Chance blessing for 25% increase at which resource drop tables are rolled.
*Playing any [[The Steel Path]] mission for +100% Resource Drop Chance and +100% Mod Drop Chance increase.
*Playing any [[Dark Sector]] missions for a Resource Drop Chance bonus ranging from +10% to +35% depending on the node. 
*Using certain Warframe abilities (e.g. {{WF|Nekros}}' {{A|Desecrate}}) to reroll enemy drop tables under certain conditions. See [[Drop Tables#Rerolling Drop Tables Mechanic]] for details.
*Having an active {{WF|Chroma}}'s {{A|Effigy}} for up to a 60% chance for enemies to drop additional {{Cc|[[Credits]]}} on kill.
*Completing all bonus objectives for each stage of a single [[Bounty]] will reward players with another roll of the final stage's drop table (containing Uncommon and Rare rarity rewards of the bounty).
*Using a {{M|Madurai Transmute Core}}, {{M|Naramon Transmute Core}}, or {{M|Vazarin Transmute Core}} to force the polarity of the resultant mod during [[Transmutation]].
*Using mods of different rarities to increase the chance of a specific mod of a desired rarity during Transmutation. See [[Transmutation#Use]] for more details.
*When transmuting four [[Riven Mods]], the resultant Riven Mod will always be of the same type as one of the transmuted Rivens.

==="Safety Nets" or "Pity System"===
WARFRAME has no known system where players are guaranteed a rarer reward from a drop table after rolling a drop table's contents multiple times. Drop chances of '''''items in drop tables''''' are static with the exception of [[Void Relic]]s of different refinements (which can be considered as separate drop tables, one for each refinement level) and multi-stage [[Bounties]] (a separate drop table is assigned per stage internally despite what the UI says).

====Lich System====
However, as of {{ver|31.1}}, players can decrease the weapon pool that an [[Lich System|Adversary/Lich]] may generate with by choosing not perform a [[Mercy]] finisher on downed Progenitors ([[Kuva Larvling]]s or [[Candidate]]s). The weapon pool will reset upon generating a new Adversary/Lich or if all possible weapons are rejected.<ref name="U31.1">"By skipping a Progenitor (choosing not to Mercy them) the spawned weapon is then put into a ‘reject’ pile for that round of Adversary generation, meaning that it will not appear again and ultimately reducing the weapon pool each time you ‘reject’.

The list of rejected weapons is cleared once you accept an Adversary and the process would start again from a clean slate for both Sister or Kuva Lich the next time you go looking for an Adversary. This list clearing applies to both Sister and Kuva Lich, meaning once the chosen Adversary is Converted or Vanquished, the list clears for both factions.

Test Cluster change: Kuva Lich/Sister of Parvos weapon reject list will now reset if you reject every possible weapon." - {{ver|31.1}} patch notes</ref>

For example, say a player is trying to get a {{Weapon|Kuva Bramma}} from a [[Kuva Larvling]], the chances of getting it naturally is {{Math|1/19|mt=y|p=y}} as of {{ver|31.1}}. Without the "safety net", it would take an expected number of {{Math|1/(1/19)}} attempts before the player sees their first Kuva Bramma with 90% of the player base seeing at least one Kuva Bramma within ~43 attempts.<ref>To get the expected (average) number of attempts for a particular Kuva/Tenet weapon, we have to determine the distribution of the number of failures needed before getting one success. In other words, the average number of attempts without seeing a particular weapon before the player finally sees that weapon. The resultant probability distribution will follow a [[wikipedia:geometric distribution|geometric distribution]]. 90% confidence level is determined using the geometric distribution's cumulative distribution function with 1/19 set as the probability for rolling a weapon.</ref> With the "safety net", all players are guaranteed (100% chance) to get one Kuva Bramma by 19 attempts, with the chance of getting a Kuva Bramma increasing rapidly with each attempt. For example:
*19 Kuva weapons in the pool ({{Math|1/19|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Drakgoon}} and skips, {{Weapon|Kuva Drakgoon}} is removed from pool on mission completion
*18 weapons ({{Math|1/18|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Seer}} and skips, {{Weapon|Kuva Seer}} is removed from pool on mission completion
*17 weapons ({{Math|1/17|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Tonkor}} and skips, {{Weapon|Kuva Tonkor}} is removed from pool on mission completion
*...
*3 weapons ({{Math|1/3|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Grattler}} and skips, {{Weapon|Kuva Grattler}} is removed from pool on mission completion
*2 weapons ({{Math|1/2|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Nukor}} and skips, {{Weapon|Kuva Nukor}} is removed from pool on mission completion
*1 weapon ({{Math|1/1|mt=y|p=y}} chance), player sees a {{Weapon|Kuva Bramma}} and chooses, pool is reset for next cycle (i.e. after current Lich is defeated)

====Archon Shards====
As of {{ver|32.3}}, [[Archon Hunt]]s feature a pity system for [[Archon Shard]]s where each time a player fails to get a Tauforged shard, the chance is increased by 20% until the player is guaranteed a Tauforged at 100%. This pity is tracked individually for each player in a squad and for each of the three shards: {{Resource|Tauforged Amber Archon Shard}}, {{Resource|Tauforged Azure Archon Shard}}, and {{Resource|Tauforged Crimson Archon Shard}}.

===Diminishing Drop Chances===
It is known that in very specific circumstances, the drop chances of certain items will decrease over multiple rolls as defined by the developers.<ref>"An Orokin Cell farming exploit was brought to our attention by not only players, but also our internal flagging system when such a method is tripped for misuse. In short, players were forcing the Hyena’s to spawn infinitely by entering/exiting rooms knowing that their Orokin Cell drop rate is 100%. As a result of this misuse, the Orokin Cell drop rate for the Hyena’s in the Razorback mission will diminish the more you spawn, to still allow for multiple drop attempts but without giving away the entire cake." - {{ver|25.8.1}} patch notes</ref><ref>"Cronus blueprint now only a guaranteed drop the first time Tolstoj is completed, % chance to drop continues to decrease on additional runs." - {{ver|7.8}} patch notes</ref>

==Calculating an Item's Drop Chance==
The following formulae are used to determine the base drop chance per item before introducing [[#Bias]] to individual items.
<math>
\text{Common Drop Chance (Per Item)} = \frac{ \text{Base Common Drop Chance} }{ \text{Number Of Common Items} }
</math>

<math>
\text{Uncommon Drop Chance (Per Item)} = \frac{ \text{Base Uncommon Drop Chance} }{ \text{Number Of Uncommon Items} }
</math>

<math>
\text{Rare Drop Chance (Per Item)} = \frac{ \text{Base Rare Drop Chance} }{ \text{Number Of Rare Items} }
</math>

<math>
\text{Legendary Drop Chance (Per Item)} = \frac{ \text{Base Legendary Drop Chance} }{ \text{Number Of Legendary Items} }
</math>

===Example Procedure===
<pre>
Say a drop table has 8 Common, 6 Uncommon, 4 Rare, and 2 Legendary drops.
The drop chances of each item rarity are (before presenting biases):

   Common: 0.755 / 8 = 0.094375           = 9.44%
 Uncommon: 0.22 / 6  = 0.0366666666667    = 3.67%
     Rare: 0.02 / 4  = 0.005              = 0.50%
Legendary: 0.005 / 2 = 0.0025             = 0.25%

Reversing operation to find chances of picking an item from a particular rarity tier:

   Common: 9.4375% × 8     = 75.5%
 Uncommon: 3.66666667% × 6 = 22%
     Rare: 0.5% × 4        = 2%
Legendary: 0.25% × 2       = 0.5%
</pre>

==<code>DropTables</code> Variables==
The following are some variables that are present within <code>/Lotus/Types/DropTables</code> enemy [[Drop Tables]].

===Bias===
'''<code>[[wikipedia:Bias_(statistics)|Bias]]</code>''' is a variable exclusive to '''<code>DropTables</code>''' that unequally weighs items within '''<code>DropTables</code>''' (through a positive (+) or negative (-) value change), even if said items have identical rarity weights. Bias can be applied to specific items within a particular '''<code>DropTable</code>''' but is not global across all. The more bias an item has (larger value), the lower its drop chance is. Conversely, the less bias an item has (smaller value), the higher its drop chance. Additionally, because bias scales from the rarity weight that the item it is impacting is assigned to, items with rarity weights that hold more weight than others will still tend to drop more often, depending on the amount of bias that is present.<ref name="void_blog" />

====Example of No Bias in Enemy Drop Tables====
[[File:EliteLancerCodex.jpg|thumb|right|400px]]
{| class="wikitable"
|+ No bias<ref name="drop_table">Obtained from the official drop table repository https://www.warframe.com/droptables on 2021-07-06</ref>
|-
| [[Elite Lancer]] || colspan=2 | Mod Drop Chance: 3.00%
|-
| || {{M|Revenge}} || Uncommon (25.29%)
|-
| || {{M|Quickdraw}} || Uncommon (25.29%)
|-
| || {{M|Redirection}} || Uncommon (25.29%)
|-
| || {{M|Razor Shot}} || Uncommon (11.06%)
|-
| || 50 [[Endo]] || Uncommon (11.06%)
|-
| || {{M|Thunderbolt}} || Legendary (0.67%)
|-
| || {{M|Undying Will}} || Legendary (0.67%)
|-
| || {{M|Crossing Snakes}} || Legendary (0.67%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization
|-
| colspan=3 align="left" | ▾ 0
| colspan=5 align="right" | 1 ▾
|-
| style="background:lightgray; color:black;" width=25.29% | Revenge
| style="background:white; color:black;" width=25.29% | Quickdraw
| style="background:lightgray; color:black;" width=25.29% | Redirection
| style="background:white; color:black;" width=11.06% | Razor Shot
| style="background:lightgray; color:black;" width=11.06% | 50 Endo
| style="background:white; color:black;" width=0.67% | <!--Thunderbolt-->
| style="background:lightgray; color:black;" width=0.67% | <!--Undying Will-->
| style="background:white; color:black;" width=0.67% | <!--Crossing Snakes-->
|-
| style="background:#bd9177;" colspan=3 | &nbsp;
| style="background:#d1d0d1;" colspan=2 | 
| style="background:#ece175;" colspan=3 | 
|-
| colspan=3 | Common (25.29% * 3 = 75.87% ≈ 75.88%)
| colspan=2 | Uncommon (11.06% * 2 = 22.12% ≈ 22.11%)
| colspan=3 | Rare (0.67% * 3 = 2.01%)
|-
|}
*Note that drop chances shown in drop tables round to the nearest two decimal places, thus calculated rarity weightings may be off from the actual/expected numbers.
*The rarity classifiers in the table considers only the final drop chance and has nothing to do with rarity weighting
<hr />
Notice that there is a clear distinction of different classes of items with the same drop chances. From here, one can deduce the rarity weightings each item used:
*Revenge, Quickdraw, and Redirection each have a 25.29% drop chance; {{MathText|25.29% * 3 &#61; 75.87%}} which is close to the Common rarity weighting after normalization
*Razor Shot and 50 Endo each have a 11.06% drop chance; {{MathText|11.06% * 2 &#61; 22.12%}} which is close to the Uncommon rarity weighting after normalization
*Thunderbolt, Undying Will, and Crossing Snakes each have a 0.67% drop chance; {{MathText|0.67% * 3 &#61; 2.01%}} which is close to the Rare rarity weighting after normalization

Alternatively, if one has a [[Codex]] entry of a particular enemy completed, the reward drops shown will be color-coded based on the rarity weighting it used. See [[#Rarity Classification]] for more details.

====Example of Bias in Enemy Drop Tables====
[[File:EidolonTeralystCodex.jpg|thumb|right|400px]]
{| class="wikitable"
|+ Bias<ref name="drop_table">Obtained from the official drop table repository https://www.warframe.com/droptables on 2021-07-06</ref>
|-
| [[Eidolon Teralyst]] || colspan=2 | Mod Drop Chance: 100.00%
|-
| || {{M|Lethal Momentum}} || Uncommon (22.22%)
|-
| || {{M|Terminal Velocity}} || Uncommon (22.22%)
|-
| || {{M|Fatal Acceleration}} || Uncommon (22.22%)
|-
| || {{M|Collision Force}} || Rare (8.33%)
|-
| || {{M|Pummel}} || Rare (8.33%)
|-
| || {{M|Crash Course}} || Rare (8.33%)
|-
| || {{M|Full Contact}} || Rare (8.33%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization
|-
| colspan=3 align="left" | ▾ 0
| colspan=4 align="right" | 1 ▾
|-
| style="background:lightgray; color:black;" width=22.22% | Lethal Momentum
| style="background:white; color:black;" width=22.22% | Terminal Velocity
| style="background:lightgray; color:black;" width=22.22% | Fatal Acceleration
| style="background:white; color:black;" width=8.33% | Collision Force
| style="background:lightgray; color:black;" width=8.33% | Pummel
| style="background:white; color:black;" width=8.33% | Crash Course
| style="background:lightgray; color:black;" width=8.33% | Full Contact
|-
| style="background:#d1d0d1;" colspan=3 | &nbsp;
| style="background:#ece175;" colspan=4 |
|-
| colspan=3 | Uncommon (22.22% * 3 = 66.66%)
| colspan=4 | Rare (8.33% * 4 = 33.32%)
|-
|}
Note that because drop chance percentages in the official drop table repository are rounded to the nearest two decimals, the total drop chance will not always add up to 100% exactly. Internally, the game will probably use floating-point values with some truncation/rounding so that:
*Actual drop chances will add up to 100% exactly or
*The RNG will not generate numbers that are outside of the reward bins
In other words, there will never be an instance where a player will get no drops after successfully getting a chance to earn a reward from some drop table.

====Another Example of Bias in Enemy Drop Tables====
[[File:FeyarchSpecterCodex.jpg|thumb|right|400px]]
{| class="wikitable"
|+ Bias<ref name="drop_table">Obtained from the official drop table repository https://www.warframe.com/droptables on 2021-07-06</ref>
|-
| [[Feyarch Specter]] || colspan=2 | Mod Drop Chance: 100.00%
|-
| || {{M|Shotgun Amp}} || Common (51.52%)
|-
| || {{M|Final Harbinger}} || Common (36.36%)
|-
| || {{M|Empowered Blades}} || Rare (6.06%)
|-
| || {{M|High Noon}} || Rare (6.06%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization
|-
| colspan=3 align="left" | ▾ 0
| colspan=4 align="right" | 1 ▾
|-
| style="background:lightgray; color:black;" width=51.52% | Shotgun Amp
| style="background:white; color:black;" width=36.36% | Final Harbinger
| style="background:lightgray; color:black;" width=6.06% | Empowered Blades
| style="background:white; color:black;" width=6.06% | High Noon
|-
| style="background:#d1d0d1;" colspan=2 | &nbsp;
| style="background:#ece175;" colspan=2 | &nbsp;
|-
| colspan=2 | Uncommon (51.52% + 36.36% = 87.88%)
| colspan=2 | Rare (6.06% * 2 = 12.12%)
|-
|}

====Example of Bias in End-of-Mission Rewards====
{| class="wikitable"
|+ Bias involved<ref name="drop_table" />
|-
| colspan=2 | [[Void Storm]] ([[Veil Proxima]])
|-
| 6X Corrupted Holokey || Uncommon (37.50%)
|-
| 1200 Endo || Uncommon (12.50%)
|-
| Sevagoth Chassis Blueprint || Uncommon (10.00%)
|-
| Sevagoth Neuroptics Blueprint || Uncommon (10.00%)
|-
| Sevagoth Systems Blueprint || Uncommon (10.00%)
|-
| Veil Resource Bundle || Rare (2.50%)
|-
| Axi O5 Relic (Radiant) || Rare (2.50%)
|-
| Axi A13 Relic (Radiant) || Rare (2.50%)
|-
| Axi N7 Relic (Radiant) || Rare (2.50%)
|-
| Axi T7 Relic (Radiant) || Rare (2.50%)
|-
| Axi G6 Relic (Radiant) || Rare (2.50%)
|-
| Axi C6 Relic (Radiant) || Rare (2.50%)
|-
| Axi I1 Relic (Radiant) || Rare (2.50%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization
|-
| colspan=12 align="left" | ▾ 0
| colspan=4 align="right" | 1 ▾
|-
| style="background:lightgray; color:black;" width=37.5% | 6X Corrupted Holokey
| style="background:white; color:black;" width=12.5% | 1200 Endo
| style="background:lightgray;" width=10% | <!--Sevagoth Chassis Blueprint -->
| style="background:white; color:black;" width=10% | <!--Sevagoth Neuroptics Blueprint -->
| style="background:lightgray; color:black;" width=10% | <!--Sevagoth Systems Blueprint -->
| style="background:white; color:black;" width=2.5% | <!--Veil Resource Bundle--> 
| style="background:lightgray; color:black;" width=2.5% | <!--Axi O5 Relic (Radiant)-->
| style="background:white; color:black;" width=2.5% | <!--Axi A13 Relic (Radiant)-->
| style="background:lightgray; color:black;" width=2.5% | <!--Axi N7 Relic (Radiant)-->
| style="background:white; color:black;" width=2.5% | <!--Axi T7 Relic (Radiant)-->
| style="background:lightgray; color:black;" width=2.5% | <!--Axi G6 Relic (Radiant)-->
| style="background:white; color:black;" width=2.5% | <!--Axi C6 Relic (Radiant)-->
| style="background:lightgray; color:black;" width=2.5% | <!--Axi I1 Relic (Radiant)-->
|-
| style="background:#ece175;" colspan=5 | &nbsp;
| style="background:#b996db;" colspan=8 |
|-
| colspan=5 | Rare (37.50% + 12.50% + (10% * 3) = 80%)
| colspan=8 | Legendary (2.50% * 8 = 20%)
|-
|}
Due to the drop table using only two rarity weightings (Rarity and Legendary), after [[#Normalization]], Rare drop percentage is {{MathText|2% / (2% + 0.5%) &#61; 80%}} and Legendary is {{MathText|0.5% / (2% + 0.5%) &#61; 20%}}. Notice that despite 6X Corrupted Holokey, 1200 Endo, and Sevagoth's component blueprints using the Rare rarity weighting, they have different drop chances individually. This is due to bias involved to reduce/increase the drop chances of individual items. If there were no bias involved at all, we would expect each Rare item to have {{MathText|80% / 5 items &#61; 16%}} and each Legendary item to have {{MathText|20% / 8 items &#61; 2.5%}}.

====Example of Bias in Bounties====
[[File:Lvl10-30CetusBountyRotA.jpg|thumb|right|400px]]
{| class="wikitable"
|+ Bias in second Cetus bounty<ref>From official drop tables, retrieved 2021-10-31</ref>
|-
| colspan=3 | Level 10 - 30 [[Cetus]] Bounty
|-
| colspan=3 | Rotation A
|-
| || colspan=2 | Stage 1
|-
| || Steel Fiber || Uncommon (25.00%)
|-
| || 200X Oxium || Uncommon (25.00%)
|-
| || 2,500 Credits Cache || Uncommon (25.00%)
|-
| || 100 Endo || Uncommon (25.00%)
|-
| || colspan=2 | Stage 2, Stage 3 of 4, and Stage 3 of 5
|-
| || Steel Fiber || Uncommon (15.08%)
|-
| || 200X Oxium || Uncommon (15.08%)
|-
| || 2,500 Credits Cache || Uncommon (15.08%)
|-
| || 100 Endo || Uncommon (15.08%)
|-
| || Gara Systems Blueprint || Rare (9.52%)
|-
| || Charged Chamber || Rare (9.52%)
|-
| || Burning Wasp || Rare (9.52%)
|-
| || Lith B4 Relic || Uncommon (11.11%)
|-
| || colspan=2 | Stage 4 of 5
|-
| || Steel Fiber || Uncommon (14.50%)
|-
| || 200X Oxium || Uncommon (14.50%)
|-
| || 2,500 Credits Cache || Uncommon (14.50%)
|-
| || 100 Endo || Uncommon (14.50%)
|-
| || Gara Systems Blueprint || Rare (9.16%)
|-
| || Charged Chamber || Rare (9.16%)
|-
| || Burning Wasp || Rare (9.16%)
|-
| || Lith B4 Relic || Uncommon (10.69%)
|-
| || 2X Control Module || Rare (3.82%)
|-
| || colspan=2 | Final Stage
|-
| || Gara Systems Blueprint || Uncommon (21.82%)
|-
| || Charged Chamber || Uncommon (21.82%)
|-
| || Burning Wasp || Uncommon (21.82%)
|-
| || Lith B4 Relic || Uncommon (25.45%)
|-
| || 2X Control Module || Rare (9.09%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization of Stage 1
|-
| colspan=3 align="left" | ▾ 0
| colspan=1 align="right" | 1 ▾
|-
| style="background:white; color:black;" width=25% | Steel Fiber
| style="background:lightgray; color:black;" width=25% | 200X Oxium
| style="background:white; color:black;" width=25% | 2,500 Credits Cache
| style="background:lightgray; color:black;" width=25% | 100 Endo
|-
| style="background:#bd9177;" colspan=4 | &nbsp;
|-
| colspan=4 | Common (25% * 4 = 100%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization of Stage 2, Stage 3 of 4, and Stage 3 of 5
|-
| colspan=5 align="left" | ▾ 0
| colspan=3 align="right" | 1 ▾
|-
| style="background:white; color:black;" width=15.08% | Steel Fiber
| style="background:lightgray; color:black;" width=15.08% | 200X Oxium
| style="background:white; color:black;" width=15.08% | 2,500 Credits Cache
| style="background:lightgray; color:black;" width=15.08% | 100 Endo
| style="background:white; color:black;" width=9.52% | Gara Systems Blueprint
| style="background:lightgray; color:black;" width=9.52% | Charged Chamber
| style="background:white; color:black;" width=9.52% | Burning Wasp
| style="background:lightgray; color:black;" width=11.11% | Lith B4 Relic
|-
| style="background:#bd9177;" colspan=4 | &nbsp;
| style="background:#d1d0d1;" colspan=4 |
|-
| colspan=4 | Common (15.08% * 4 = 60.32%)
| colspan=4 | Uncommon (9.52% * 3 + 11.11% = 39.67%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization of Stage 4 of 5
|-
| colspan=5 align="left" | ▾ 0
| colspan=4 align="right" | 1 ▾
|-
| style="background:white; color:black;" width=14.50% | Steel Fiber
| style="background:lightgray; color:black;" width=14.50% | 200X Oxium
| style="background:white; color:black;" width=14.50% | 2,500 Credits Cache
| style="background:lightgray; color:black;" width=14.50% | 100 Endo
| style="background:white; color:black;" width=9.16% | Gara Systems Blueprint
| style="background:lightgray; color:black;" width=9.16% | Charged Chamber
| style="background:white; color:black;" width=9.16% | Burning Wasp
| style="background:lightgray; color:black;" width=10.69% | Lith B4 Relic
| style="background:white; color:black;" width=3.82% | 2X Control Module
|-
| style="background:#bd9177;" colspan=4 | &nbsp;
| style="background:#d1d0d1;" colspan=4 |
| style="background:#ece175;" colspan=1 |
|-
| colspan=4 | Common (14.50% * 4 = 58%)
| colspan=4 | Uncommon (9.16% * 3 + 10.69% = 38.17%)
| colspan=1 | Rare (3.82%)
|-
|}
{| width=100% style="text-align:center;"
|+ Bar visualization of Final Stage
|-
| colspan=3 align="left" | ▾ 0
| colspan=2 align="right" | 1 ▾
|-
| style="background:white; color:black;" width=21.82% | Gara Systems Blueprint
| style="background:lightgray; color:black;" width=21.82% | Charged Chamber
| style="background:white; color:black;" width=21.82% | Burning Wasp
| style="background:lightgray; color:black;" width=25.45% | Lith B4 Relic
| style="background:white; color:black;" width=9.09% | 2X Control Module
|-
| style="background:#d1d0d1;" colspan=4 | &nbsp;
| style="background:#ece175;" colspan=1 |
|-
| colspan=4 | Uncommon (21.82% * 3 + 25.45% = 90.91%)
| colspan=1 | Rare (9.09%)
|-
|}
*Lith B4 Relic has a slight bias applied, making it more likely to drop than the rest of the rewards that use the uncommon rarity weighting.

===Attenuation (global bias)===
'''<code>[[wiktionary:attenuation|Attenuation]]</code>''' is a variable exclusive to '''<code>DropTables</code>'''. The boolean '''<code>OverrideLevelAdjustedBiasAtten</code>''' determines if attenuation is present in a '''<code>DropTable</code>''' or not. As the attenuation value increases, the drop chance of an item should decrease. However, because of how minor its set value ('''0.5''') is (from one of the boolean's secondary variables, '''<code>RareAttenMax</code>'''), and that it impacts '''<code>DropTables</code>''' globally instead of individual items, it is impossible to accurately determine if it has a noticeable impact on items at all.<ref name="void_blog" /><ref>{{Ref|title=Datamining shows DE messing up Steel Path droptables again|author=DailyPermit|year=2020|month=8|day=17|publisher=Reddit|url=https://www.reddit.com/r/Warframe/comments/ibery2/datamining_shows_de_messing_up_steel_path/|access-date=2022-11-20|archive-url=https://web.archive.org/web/20221120180134/https://www.reddit.com/r/Warframe/comments/ibery2/datamining_shows_de_messing_up_steel_path/|archive-date=2022-11-20|extra=Snapshot of Steel Path Eximus drop tables shows presence of a "OverrideLevelAdjustedBiasAtten" field}}</ref>

==<code>MissionDecks</code> Variables==
===Reward Seeds===
{{UpdateMe|"Despite the '''<code>SRand</code>''' variable (the seeding for the random number generator, a [[wikipedia:C_mathematical_functions#Random_number_generation|pseudo-random integer between 0 and <code>RAND_MAX</code>]])" does not match EE.log giving out a negative value for SRand}}
'''<code>rewardSeed</code>''' is a variable exclusive to '''<code>MissionDecks</code>'''. It is a 64-bit signed integer that determines the '''<code>missionReward</code>''' players receive at the end of a mission. It is granted to you by the game's servers at the start of the mission and remains with you until its completion. '''<code>rewardSeeds</code>''' are given to the host, and members of the host's group receive the '''<code>sessionId</code>''' in order to participate in the same [[matchmaking]] session. You will only receive a '''<code>rewardSeed</code>''' when your client needs to distribute it to players in a group (as the host). This means that you will receive a '''<code>rewardSeed</code>''' if you begin a Public, Friends Only, or Invite Only session, but if you begin a Solo session, you will not be given a '''<code>rewardSeed</code>'''. Despite the '''<code>SRand</code>''' variable (the seed for the random number generator) being different for each player, each player will always receive the same '''<code>missionReward</code>''' as the host because of their identical '''<code>sessionIds</code>'''.<ref name="void_blog" /><ref name="EE.log">This process can be partially observed in the game engine's log: [[EE.log]]</ref>

Examples of valid reward seeds:
*<code>5981559039678745352</code>
*<code>-2947528797702211811</code>
*<code>-1912700803863294092</code>
*<code>-3758848590968623960</code>
*Any value in the range of <code>−(2^63) to 2^63 − 1</code> or <code>−9223372036854775808 to +9223372036854775807</code> inclusive

;Samples in [[EE.log]]
Note that when players start a matchmaking session, the rewardSeed will be set to <code>-1</code> before being updated with a random value.
<pre>
3.260 Sys [Diag]: SRand seeded with: -3443681654817279495
...
4217.029 Net [Info]: MatchingServiceWeb::HostSession - settings: {"maxPlayers":4,"minPlayers":1,"privateSlots":0,"scoreLimit":15,"timeLimit":900,"gameModeId":0,"eloRating":28,"regionId":3,"difficulty":0,"hasStarted":false,"enableVoice":true,"matchType":"NORMAL","maps":[],"originalSessionId":"","usingPlayNow":false,"customSettings":"","rewardSeed":-1,"guildId":"","buildId":526217994,"freePublic":3,"freePrivate":0}
...
4217.154 Net [Info]: HostSessionCallback
4217.154 Net [Info]: sessionId=60e53502b0a65e27a219ad33
4217.154 Net [Info]: HostSessionDone (1, sessionId=60e53502b0a65e27a219ad33, rewardSeed=5981559039678745352)
...
4227.948 Net [Info]: NAT bound for client to <PLAYER_IP_ADDRESS>:4955
4228.005 Net [Info]: DeleteSessionCallback(1, {"sessionId":"60e53502b0a65e27a219ad33","rewardSeed":-2947528797702211811}
4228.005 Net [Info]: Deleted session
...
4231.370 Net [Info]: IRC out: QUIT :Logged out of game
4231.476 Net [Info]: DeleteSessionCallback(1, {"rewardSeed":-1912700803863294092}
4231.477 Net [Info]: Deleted session
</pre>

==Prior to {{ver|10.6.2}}==
{{Speculation}}
Prior to {{ver|10.6.2}} changes, WARFRAME's random number generator had a flawed distribution<ref name="steve_forum" />, resulting in abnormal number of streaks of bad/good luck in the reward drops compared to a more "randomly" distributed RNG. Recall that WARFRAME uses the following formula for RNG in endless missions:

:<math>X_n = (a(X_{n-1}) + c) \mod m</math> 

Where <math>X</math> is the [[wikipedia:sequence|sequence]] of pseudorandom values, and
:<math> m = 1</math> — "modulus"
:<math> a = 1</math> — "multiplier"
:<math> c,\, 0 \le c < m</math> — "increment", randomly chosen based on seed with truncation of lower-order bits
:<math> X_0, 0 \le X_0 \le 1</math> — initial seed value based on seed
:<math> n,\, n > 0</math> — current iteration or reward rotation number, an integer

When players enter a mission, they get a random seed. Depending on that seed, they get a value between 0 and 1 inclusive which we will call "initial seed". After reaching a reward rotation, players get a random reward based on their initial seed.

On the next reward rotation, players will get a new random number depending on the seed. This new random number will be added to the initial seed. In other words, if the initial seed was 0.5, the interval picking number will be equal to {{MathText|0.5 + <code>increment</code>}}. However, this "random" value is the same for every checkpoint after due to truncation in the RNG.<ref name="steve_forum" /> For example, the 3rd reward rotation would be determined by {{MathText|0.5 + <code>increment</code> + <code>increment</code> or 0.5 + (2 * <code>increment</code>)}}.

The issue with this RNG is that it is more deterministic as one with this knowledge and the loot table drop chances (previously hidden from players until 2021-06-28 or just before {{ver|21}}<ref>https://forums.warframe.com/topic/809777-warframe-drop-rates-data/ - Warframe Drop Rates Data forum post</ref>) can determine their initial seed and on the 2nd reward rotation determine what increment is (approximately). By extension, one can calculate the approximate number of reward rotations until players get their desired reward. Another issue with this method is that players that rolled a low <code>increment</code> value may experience getting the same reward multiple reward rotations in a row; this is more prevalent if the player's first reward is a common item though it is possible for a player to receive consecutive rare drops with a very low or very high increment value.<ref name="steve_forum" />

===Sample Scenario (pre-{{ver|8.1}})===
;Tier 3 Defense drop table<ref name="reddit">{{Ref|title=Defense Mission Rewards And Scaling|author=Pwnatron|year=2013|month=6|day=3|publisher=Reddit|url=https://www.reddit.com/r/Warframe/comments/1fl18h/defense_mission_rewards_and_scaling/|access-date=2022-07-26|archive-url=https://web.archive.org/web/20210710214021/https://www.reddit.com/r/Warframe/comments/1fl18h/defense_mission_rewards_and_scaling/|archive-date=2021-07-10}}</ref>
*Order matters in determining drops (pre-{{ver|10.6.2}} at least).
*Drop chances are rounded to nearest two decimal places.
*This pre-{{ver|8.1}} drop table are from a time where there is no such thing as AABCCCC... [[Rotation|reward rotations]] (i.e. three different drop tables labeled A, B, and C). Instead, each reward rotation pulls from the same drop table.
**Each mission type has three difficulty tiers, each with a separate drop table labeled "Tier 1", "Tier 2", and "Tier 3" corresponding to "Easy", "Medium", and "Hard" respectively. Difficulty levels depend on starting enemy level ranges.
{| class="wikitable"
|-
| colspan=3 | Tier 3 [[Defense]]
|-
| || Hellfire || 18.97%
|-
| || Heated Charge || 18.97%
|-
| || Convulsion || 3.16%
|-
| || Deep Freeze || 0.15%
|-
| || North Wind || 0.15%
|-
| || Shocking Touch || 0.15%
|-
| || North Wind || 0.15%
|-
| || Hellfire || 18.97%
|-
| || Stormbringer || 3.16%
|-
| || Cryo Rounds || 0.15%
|-
| || Split Chamber || 0.15%
|-
| || Barrel Diffusion || 0.15%
|-
| || Hell's Chamber || 0.15%
|-
| || Stretch || 0.15%
|-
| || Redirection || 3.16%
|-
| || Streamline || 18.97%
|-
| || Enemy Sense || 3.16%
|-
| || Enemy Sense || 0.15%
|-
| || Rush || 0.15%
|-
| || Focus || 3.16%
|-
| || Banshee Helmet Blueprint || 3.16%
|-
| || Banshee Chassis Blueprint || 0.15%
|-
| || Banshee Systems Blueprint || 3.16%
|-
| || Orokin Tier 3 Extermination Key || 0.15%
|}
{| width=100% style="table-layout: fixed;"
|+ Bar visualization of the above drop table
| style="background:lightgray; color:black;" width=18.97% | Hellfire
| style="background:white; color:black;" width=18.97% | Heated Charge
| style="background:lightgray; color:black;" width=3.16% | <!--Convulsion-->
| style="background:white; color:black;" width=0.15% | <!--Deep Freeze-->
| style="background:lightgray; color:black;" width=0.15% | <!--North Wind-->
| style="background:white; color:black;" width=0.15% | <!--Shocking Touch-->
| style="background:lightgray; color:black;" width=0.15% | <!--North Wind-->
| style="background:white; color:black;" width=18.97% | Hellfire
| style="background:lightgray; color:black;" width=3.16% | <!--Stormbringer-->
| style="background:white; color:black;" width=0.15% | <!--Cryo Rounds-->
| style="background:lightgray; color:black;" width=0.15% | <!--Split Chamber-->
| style="background:white; color:black;" width=0.15% | <!--Barrel Diffusion-->
| style="background:lightgray; color:black;" width=0.15% | <!--Hell's Chamber-->
| style="background:white; color:black;" width=0.15% | <!--Stretch-->
| style="background:lightgray; color:black;" width=3.16% | <!--Redirection-->
| style="background:white; color:black;" width=18.97% | Streamline
| style="background:lightgray; color:black;" width=3.16% | <!--Enemy Sense-->
| style="background:white; color:black;" width=0.15% | <!--Enemy Sense-->
| style="background:lightgray; color:black;" width=0.15% | <!--Rush-->
| style="background:white; color:black;" width=3.16% | Focus
| style="background:lightgray; color:black;" width=3.16% | <!--Banshee Helmet Blueprint-->
| style="background:white; color:black;" width=0.15% | <!--Banshee Chassis Blueprint-->
| style="background:lightgray; color:black;" width=3.16% | <!--Banshee Systems Blueprint-->
| style="background:white; color:black;" width=0.15% | <!--Orokin Tier 3 Extermination Key-->
|-
| ↑ 0
| ↑ 0.1897
| colspan=20 | ↑ 0.3794
| colspan=3 align="right" | 1 ↑
|-
|}

For example, in a pre-{{ver|8.1}} scenario where a player starts a Tier 3 Defense mission<ref name="reddit" />:
# At Wave 5, they get {{M|Heated Charge}}. Now they know their initial seed was between 0.1897 inclusive and 0.3794 exclusive. The way this is determined is:
## Create an interval between 0 inclusive and 1 exclusive consisting of all the possible rewards (note that the sum of drop chances is 1 or 100%). For example, Hellfire is 0.0 - 0.1897, Heated Charge is 0.1897 - 0.3794, etc.
## Find out where the initial seed fits in and that is the item players will get. In this case, 0.1897 ≤ <code>initial_seed</code> < 0.3794
# At Wave 10, they get {{M|Heated Charge}} again. Now they know their increment was approximately between 0 inclusive and 0.1897 exclusive or between 0.8104 inclusive and 1 exclusive.
#* 0.1897 ≤ {{MathText|<code>initial_seed</code> + <code>increment</code> mod 1}} < 0.3794
#** If <code>initial_seed=0.2111</code> and <code>increment=0.1512</code>, then {{MathText|(0.2111 + 0.1512) mod 1 &#61; 0.3623}}
#** If <code>initial_seed=0.3345</code> and <code>increment=0.8556</code>, then {{MathText|(0.3345 + 0.8556) mod 1 &#61; 0.1901}}
#** If <code>initial_seed=0.3793</code> and <code>increment=0.9999</code>, then {{MathText|(0.3793 + 0.9999) mod 1 &#61; 0.3792}}
# In order to get the Orokin Tier 3 Extermination key, the last drop in the table, players would need to get a value between 0.9985 inclusive and 1 exclusive.
#* 0.9985 ≤ {{MathText|<code>initial_seed</code> + (5 * <code>increment</code>) mod 1}} < 1
#** If <code>initial_seed=0.2111</code> and <code>increment=0.1512</code>, then players will need to play at least 574 reward rotations to get their first key drop<br />{{MathText|0.2111 + (574 * 0.1512) mod 1 &#61; 0.9671}}
#** If <code>initial_seed=0.3345</code> and <code>increment=0.8556</code>, then players will need to play at least 217 reward rotations to get their first key drop<br />{{MathText|0.3345 + (217 * 0.8556) mod 1 &#61; 0.9671}}
#** If <code>initial_seed=0.3793</code> and <code>increment=0.9999</code>, then players will need to play at least 3,794 reward rotations to get their first key drop, with the next 14 reward rotations also providing the key drop (15 consecutive rare rewards!)<br />{{MathText|0.3793 + (3794 * 0.9999) mod 1 &#61; 0.9999}}
<!--Not sure about the validity of this statement since the referenced Reddit post had the interval wrong for Orokin Tier 3 Extermination key: #* If their increment is big, the chance to hit 0.985 - 1.0 interval for the Orokin Tier 3 Extermination key is really small.-->

====Sample Code====
The following Lua snippet provides a sample sequence of one thousand values (i.e. 1,000 reward rotations pre-{{ver|8.1}}) based on the above scenario if <code>initial_seed=0.2111</code> and <code>increment=0.1512</code>:
<syntaxhighlight lang="lua">
local initial_seed = 0.2111
local increment = 0.1512
local previous = initial_seed

-- Rotation #574, #865 will hit the threshold needed for 
-- Orokin Tier 3 Extermination key
for i = 1, 1000, 1 do
    local result = (previous + increment) % 1
    previous = result
    if (result >= 0.9985 and result < 1) then
        print(i, result, "hit") 
    else
        print(i, result)
    end
end
</syntaxhighlight>

==Other Uses of RNG==
In WARFRAME, RNG is not just used to determine whether or not an item will drop for players. It is also used in, but not limited to:
{{Column|2|
*Graphics like special effects (SFX)<ref name="steve_forum" /> and bullet decals
*General gameplay
**Weapon mechanics such as [[Critical Hit]]s, [[Status Effect]]s, [[Multishot]], [[Accuracy]], and [[Recoil]]
**Stat bonus on [[Kuva Lich]] or [[Sisters of Parvos]] weapons and [[Railjack#Armaments|Railjack Armaments]]
**[[Buff & Debuff]] chance to trigger (such as from [[Arcane Enhancement]]s)
**[[Enemy Behavior|Enemy AI]] and spawning mechanics through [[AI Director]]
**Assassin appearances such as [[Stalker]] or Syndicate death squads
**[[Mining]], [[Fishing]], [[Conservation]], and [[Hacking]] minigames
**[[Matchmaking]]
**The Warframes chosen for the week's [[Helminth#Invigoration|Helminth Invigoration]]
*Mods
**[[Transmutation]]
**[[Riven Mods]]
*Rewards
**[[Nightwave]] offerings
**[[Daily Tribute]] rewards
**[[Ticker]] decorations, debt-bonds, and [[Railjack/Crew|NPC crew]] offerings
**Daily special for [[Hok]], [[Rude Zuud]], and [[Roky]]
**[[Entrati]] family trade-ins for tokens/standing
*[[World State]]
**[[Invasion]]s availability and rewards
**[[The Steel Path]] incursions
**[[Syndicate]] missions
**[[Arbitrations]]
**[[Void Fissure]]s
**[[Nightwave]] challenges
**[[Sortie]] missions
**[[Bounty]] types and bounty stages each [[Landscape]] cycle (2.5 hours)
**[[Nightmare Mode]] missions
**Daily [[Darvo]] Deals
**Sentient Anomaly location in [[Veil Proxima]]
*[[Lich System]]
**Weapon that is shown when Progenitor enemy is downed
**[[Requiem Mods]] sequence
**Reward tax on completing a node
**Requiem Murmur gain on mercy kills
**Mission node influence
**Whether or not the Lich spawns with an [[Ephemera]]
*Animations
**[[Parazon]] kills
**Idle animations
*Environment
**Generation of mission [[Tile Sets]] that comprise of a map
**Movement of [[Kuva Fortress]] across the [[Star Chart]]
**Weather system in [[Landscape]]s
*Physics
**Ragdolls
**Projectile trajectory
*[[Sound]]
**Chosing which dialogue to play from NPCs, enemies, and vendors
**Filters and modulation of in-game transmissions<ref>"Lotus 2.0! Lotus has recently had a major overhaul. Most of her lines have been re-recorded and now sound more consistent across the entire game. Lotus now uses a brand new DSP system to playback her audio files. Her voice has a more dynamic sound that makes use of some digital audio randomization so her voice effect will sound slightly different every time it plays." - {{ver|11.3}} patch notes</ref>
**Dynamic ambient/combat [[music]]
**Weapon sounds
**[[Kuva Lich]] and [[Sisters of Parvos]] voice profiles
*Beast [[Companion]]s
**[[Kubrow Cosmetics|Kubrow]] and [[Kavat Cosmetics|Kavat fur coat colors and patterns]]
}}

==External Links==
*{{Ref|title=Floating Point Numbers|first=Michael|last=Borgwardt|url=https://floating-point-gui.de/formats/fp/|access-date=2022-02-14|archive-url=https://web.archive.org/web/20220214220705/https://floating-point-gui.de/formats/fp/|archive-date=2022-02-14}}

;RNG
*{{Ref|title=Random Number Generation in Warframe|first=Jordan|last=Navarro|year=2016|url=https://navarroj.me/WarframeRNG.html|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209223957/https://navarroj.me/WarframeRNG.html|archive-date=2022-02-09}}
*{{Ref|title=Introduction to Randomness and Random Numbers|first=Mads|last=Haahr|url=https://www.random.org/randomness/|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224019/https://www.random.org/randomness/|archive-date=2022-02-09}}
*{{Ref|title=Analysis of an On-line Random Number Generator|first=Louise|last=Foley|year=2001|month=4|url=https://www.random.org/analysis/Analysis2001.pdf|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224107/https://www.random.org/analysis/Analysis2001.pdf|archive-date=2022-02-09}}
*{{Ref|title=Implementing Weighted RNG in Unity|first=Harvey|last=Limbo|year=2021|month=6|day=8|url=https://limboh27.medium.com/implementing-weighted-rng-in-unity-ed7186e3ff3b|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224118/https://limboh27.medium.com/implementing-weighted-rng-in-unity-ed7186e3ff3b|archive-date=2022-02-09}}
*{{Ref|title=A Faster Weighted Random Choice|first=Bruce|last=Hill|year=2017|month=2|day=2|url=https://blog.bruce-hill.com/a-faster-weighted-random-choice|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224220/https://blog.bruce-hill.com/a-faster-weighted-random-choice|archive-date=2022-02-09}}
*{{Ref|title=Pseudo Random Numbers in a Range and Modulo Bias|first=David|last=Egan|year=2020|month=6|day=8|url=https://www.dev-notes.eu/2020/06/Pseudo-Random-Numbers-in-a-Range-and-Modulo-Bias/|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224440/https://www.dev-notes.eu/2020/06/Pseudo-Random-Numbers-in-a-Range-and-Modulo-Bias/|archive-date=2022-02-09}}
*{{Ref|title=Loot Drop Tables|first=Daniel|last=Cook|year=2014|month=12|day=8|url=https://lostgarden.home.blog/2014/12/08/loot-drop-tables/|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224416/https://lostgarden.home.blog/2014/12/08/loot-drop-tables/|archive-date=2022-02-09}}
*{{Ref|title=Noise-Based RNG|first=Squirrel|last=Eiserloh|year=2017|month=3|url=https://www.youtube.com/watch?v=LWFzPP8ZbdU|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224552/https://www.youtube.com/watch?v=LWFzPP8ZbdU|archive-date=2022-02-09|youtube-id=LWFzPP8ZbdU|channel=GDC|channel-id=UC0JB7TSe49lg56u6qH8y_MQ|extra=During Game Developers Conference 2017}}
*{{Ref|title=Math for Game Programmers: Parallel Random Number Generation|first=Manny|last=Ko|year=2015|month=3|url=https://www.youtube.com/watch?v=qO8FAQvlgX0|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224711/https://www.youtube.com/watch?v=qO8FAQvlgX0|archive-date=2022-02-09|youtube-id=qO8FAQvlgX0|channel=GDC|channel-id=UC0JB7TSe49lg56u6qH8y_MQ|extra=During Game Developers Conference 2015}}
*{{Ref|title=The Two Types of Random in Game Design|first=Mark|last=Brown|year=2020|month=1|day=14|url=https://www.youtube.com/watch?v=dwI5b-wRLic|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224805/https://www.youtube.com/watch?v=dwI5b-wRLic|youtube-id=dwI5b-wRLic|channel=Game Maker's Toolkit|channel-id=UCqJ-Xo29CKyLTjn6z2XwYAw|archive-date=2022-02-09}}

;RNG in other games
*{{Ref|title=Vault Hunting 101: A Guide to RNG and LOOT!|author=VaultHunter101|year=2015|month=12|day=29|url=https://forums.gearboxsoftware.com/t/vault-hunting-101-a-guide-to-rng-and-loot/1153869|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224742/https://forums.gearboxsoftware.com/t/vault-hunting-101-a-guide-to-rng-and-loot/1153869|archive-date=2022-02-09|extra=RNG in [[wikipedia:Borderlands (series)|Borderlands]] series}}
*{{Ref|title=Pseudorandom number generation in Pokémon|year=2021|month=11|day=2|url=https://bulbapedia.bulbagarden.net/wiki/Pseudorandom_number_generation_in_Pok%C3%A9mon|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224804/https://bulbapedia.bulbagarden.net/wiki/Pseudorandom_number_generation_in_Pok%C3%A9mon|archive-date=2022-02-09|extra=On Bulbapedia, the community-driven [[wikipedia:Pokémon|Pokémon]] encyclopedia}}
*{{Ref|title=RNG|author=UncommentatedPannen|year=2016|month=5|day=15|url=https://www.youtube.com/watch?v=MiuLeTE2MeQ|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224921/https://www.youtube.com/watch?v=MiuLeTE2MeQ|archive-date=2022-02-09|youtube-id=MiuLeTE2MeQ|channel=UncommentatedPannen|channel-id=UC5miyvhPsWWyfTulnJ43koQ|extra=About how RNG is used in [[wikipedia:Super Mario 64|Super Mario 64]]}}
*{{Ref|title=Archive for the 'Probability in Game Design' Category|first=Neil|last=Brown|url=https://sinepost.wordpress.com/category/mathematics/probability/probability-in-game-design/|access-date=2022-02-09|archive-url=https://web.archive.org/web/20220209224855/https://sinepost.wordpress.com/category/mathematics/probability/probability-in-game-design/|archive-date=2022-02-09|extra=Featuring XCOM series}}

==References==
*[[User blog:FINNER/Warframe Expected & Nearly Guaranteed Numbers - An Explanation]]

{{Reflist}}

==Patch History==
{{Scrollbox/Article|
{{ver|31.1}}
;ADVERSARY WEAPON GENERATION - QUALITY OF LIFE CHANGE

As the pool of Adversary weapons grows and your checklist fills out, the natural chance of finding a Progenitor (Larvling or Candidate) with the exact weapon you desire shrinks. This Adversary Weapon Generation Quality of Life change is meant to reduce randomness over time of what weapon a Progenitor Candidate (Sister) or Larvling (Kuva Lich) can spawn with.

;How it works&#58;

By skipping a Progenitor (choosing not to Mercy them) the spawned weapon is then put into a ‘reject’ pile for that round of Adversary generation, meaning that it will not appear again and ultimately reducing the weapon pool each time you ‘reject’.

The list of rejected weapons is cleared once you accept an Adversary and the process would start again from a clean slate for both Sister or Kuva Lich the next time you go looking for an Adversary. This list clearing applies to both Sister and Kuva Lich, meaning once the chosen Adversary is Converted or Vanquished, the list clears for both factions.

'''''Test Cluster change:''' Kuva Lich/Sister of Parvos weapon reject list will now reset if you reject every possible weapon.''

{{ver|10.6.2}}<br />
Improved distribution of random numbers generated by RNG. More information: https://forums.warframe.com/topic/128402-rng-algorithm-bugschanges/

NOV 5th, 2013 - RNG ALGORITHM CHANGES

If you are one of those players that feel like the RNG Gods are angry with you, starting today you may begin to notice a more fair and balanced hand from these divine beings.

Glen (our Tech Director) identified and fixed a serious distribution flaw with random number generation (RNG) in Warframe. While enemy drops were not seriously affected, a truncation in the random 'seed' within the mission reward script could result in a terrible chain of bad luck. While some players may have benefited from this (a chain of good luck) the distribution was terrible.

For context: Games use a lot of random numbers for things other than drops; for example when you blast one of those damned security cameras and a shower of sparks explodes out of it the each particle’s direction is determined by an RNG. Since games need a lot of RNG for effects and other things we actually have a very optimized RNG to make the game run quickly – the problem is you trade entropy (how random it is) for speed.

The RNG for drops needed to be slow and good to be fair and truly reflect the intended drop rates. The new code changes embraces a much slower and entropic means of determining drops of all kinds - weapons, Warframe parts, etc.

I'm very sorry for the frustration this has caused. We are committed to preventing future regression through automated tests... Attached to this post are contrast-boosted images from these tests. The bugged RNG, which is plainly giving dreadful runs. The 'fast' RNG without the truncation error - much better but still with an obvious pattern. Lastly, Glen's new code which shows a vastly improved distribution.

Thank you for reading and happy hunting Tenno!

<gallery>
RNGChangesBugged.png
RNGChangesFast.png
RNGChangesFixed.png
</gallery>
Left to right: Bugged, Fast, Fixed (new hotness)

These pictures show the output of each RNG technique repeatedly flipping a coin: White is heads, Black is tails. In order for the loot tables to be fair and well distributed you want your RNG to output something that looks like static (which the new approach does).
}}

{{MechNav}}
[[Category:Mechanics]]
[[Category:Real-World References]]
[[Category:Development]]