编辑“科技”（章节）

== The card system ==
{{SVersion|3.3}}
[[File:Card system.png|thumb|400px|The "card" system. Every time a research project is to be initiated, the game will draw a hand of cards like this one from which the player then can pick one technology to research.]]
Although the underlying technology system is based on the familiar ''tech tree'' structure, it does away with its standard interaction/presentation in favor of the ''card shuffle'' approach. This injects a semi-random element into research, making it somewhat less predictable as well as more non-linear.

Whenever the player is prompted to initiate a research project, the game gives them a "hand of cards" consisting of a semi-random selection of technologies available for research which are picked randomly from a hidden "deck of cards" consisting of all valid research options that can appear.

Technologies are divided into 6 levels (T0 to T5) of advancement. Higher tier technologies require obtaining a certain number of technologies from the preceding tier in the same area of research (set at 6 for all tiers<ref>See {{path|common/technology/tier/00_tier.txt}} for details.</ref>) before they become available as research alternatives.

Every time the player meets the requirements for a given technology to become obtainable, the technology in question is added into the main "card deck" and will then have a chance of appearing in the "card hand" whenever the game draws a new hand for the player to pick from. There are one basic parameter affecting a tech's chances of appearing in a given card hand:

* ''Weight'' – A base value denoting the ''relative'' chance (out of all the valid options) of a particular technology to be drawn as an alternative. This may be further modified by an empire's composition (ethics, civics, etc.) and its current state (scientist's traits, past tech, etc.).

To further increase variation, a tech which appeared as an alternative in the previous card hand will have its weight set to 0 in the next prompt.

As a rule of thumb, the more advanced a technology is, the lower its weight (and the higher its cost). Systematically important techs (e.g. terraforming) have a higher weight (typically between 150% and double normal) to help ensure empires get a chance to research them, whereas {{tech|rare|rare technologies}} have significantly lower weight (typically one-eighth normal without the matching expertise). Some factors increase the weight of rare techs:
<!-- These factors are omitted from [[Society research]] because they're (almost) universal. Don't put other modifiers here e.g. expertise because they vary. -->
* Being in a level 3 or higher [[File:Federation research.png|21px]] Research Cooperative [[federation]] with another member who knows the tech doubles the weight.
* The [[File:Ap technological ascendancy.png|21px]] Technological Ascendancy ascension perk increases the weight of {{tech|rare|rare technologies}} by 50%.

=== Example ===
Let's assume the game draws a card hand of 3 techs: {{icon|Armored Torpedoes tech|21px}} Armored Torpedoes, {{icon|Autocannons tech|21px}} Autocannons, and {{iconify|Exotic Gas Refining|21px}}. Additionally, the lead engineering scientist has a {{iconify|Propulsion|21px}} field expertise (matching Armored Torpedoes) and the previous card hand had {{icon|Autocannons tech|21px}} Autocannons as an available option.

<math>\text{Total weight} = \text{Armored Torpedoes weight}\, \cdot\, \text{expertise bonus} +\, \text{Autocannons weight}\, +\, \text{Exotic Gas Refining weight}</math>

<math>\text{Total weight} = 75 \cdot 1.25\, +\, \frac{75}{2}\, +\, 170 = 93.75 +\, 37.5 +\, 170 = 301.25</math>

If these were the only three valid techs and only one tech were to be drawn, then each tech's chances of being drawn would be '''29.1%''', '''12.5%''', and '''56.4%''' respectively (rounded to 1 decimal place). Realistically there are usually many more valid picks and so the probability of picking any given tech is significantly lower than the figures given here.

=== Research alternatives ===
{{SVersion|3.3}}
Each card hand drawn will contain 3 research alternatives, which may be further increased by 1 for each of the following:
* {{icon|edict}} Scientific Revolution unity ambition
* {{icon|self-evolving logic|24px}} Self-Evolving Logic technology
* [[File:Tradition discovery science division.png|24px]] Science Division / Mindlink / Research Path Optimization discovery tradition
* {{iconify|Natural Neural Network}} civic
* {{iconify|Static Research Analysis}} civic
* {{iconify|Research Cooperative}} level 2

Additionally, some research cards may be gained as ''permanent alternatives''. They appear below the regular alternatives and are distinguished from them by a {{tech|acquire|golden}} border surrounding the tech card's bezel. These alternatives are usually acquired (along with some partial progress) through post-battle debris analysis, from special projects or [[event]] chains. These options will always appear as available options when drawing a new card hand and will remain as such until completed.

If need be, it is possible to change an on-going research project at any point – without incurring penalties – in order to continue researching it at a later time. It is important to note, however, that the saved progress does ''not'' scale with changes occurring to technology costs (for better or for worse). This tends to lead to the tech's completion percentage getting lower as the empire continues to further exceed its administrative capacity.

As opposed to a permanent alternative, there is no guarantee that the technology in question will appear in the next card hand drawn.