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# Changes

## Technology

, 8 months ago
no edit summary
{{Version|1.9}}
{{Technav}}
''Technology'' in Stellaris is divided into 3 research areas with each area corresponding with one of the research resources: {{iconify|Engineering|21px}}, {{iconify|Physics|21px}} and {{iconify|Society|21px}}. Additionally, each of the ~300 techs belongs to one of 12 field expertise scattered subcategories divided between the areas (most appearing pre-dominantly in one area though not exclusively).
The user interaction aspect utilizes a ''card shuffle'' approach rather than a traditional ''tech tree'' presentation, thereby introducing an element of semi-randomness into the system.
== Research areas & fields ==
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[[File:UI tech.png|right|thumb|400px|Technology interface. Every slot here can have one research project active at a time and every research area has its own slot.]]There are three different main ''research areas''in-game, with each area corresponding with one of the research resources. Additionally, each research area has multiple subcategories, for a total of 12 such subcategories, and every tech belongs to one of 12 fields of expertise scattered between the areasthese subcategories.
The areas and their fields subcategories are as follows:
'''{{icon|Engineering}} [[Engineering research]]'''
== The card system ==
{{SVersion|2.0}}
[[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.
When Whenever the player is prompted for to initiate a research prospectproject, the system presents game gives them a "hand of cards" consisting of a select subset semi-random selection of technologies available for research alternatives which are picked randomly from a pool hidden "deck of cards" consisting of all the valid research optionsthat can appear.
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 two basic parameters affecting a tech's chances of appearing as viable research alternativesin a given card hand:
* ''Tiers'' - 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.
* ''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, and etc.) and its current state (scientist's traits, past tech, and etc.).
To further increase variation, a tech which appeared as an alternative in the previous research prompt card hand will have its weight halved<ref name="defines">See {{path|defines}} for details.</ref> in the next prompt.
The range of costs for technologies in each tier is as follows:<ref>See {{path|common/scripted_variables/00_scripted_variables.txt}} for details.</ref>
; Example
Let's assume the game draws a pool card hand of 3 techs: {{icon|Armored Torpedoes tech|21px}} Armored Torpedoes, {{icon|Autocannons tech|21px}} Autocannons, and {{iconify|Orillium Extraction|21px}}. Additionally, the lead engineering scientist has a {{iconify|Propulsion|21px}} field expertise and the previous card hand had {{icon|Autocannons tech|21px}} Autocannons appeared as an available option in the previous prompt.
$\text{Total weight} = \text{Armored Torpedoes weight}\, +\, \text{Autocannons weight}\, +\, \text{Orillium Extraction weight}$
$\text{Total weight} = 70 \cdot 1.25\, +\, \frac{75}{2}\, +\, 180 = 87.5 +\, 37.5 +\, 180 = 305$
If a tech were to be picked at random, then each tech's chances of being drawn would be '''28.7%''', '''12.3%''', and '''59%''' respectively.
'''Note:''' Tiers, weights, and what modifiers affecting it are ''hidden'' parameters. That being said, an expertise in a tech's field is likely to increase its weight (and therefore appearance).
== Research alternatives ==
{{SVersion|1.9}}
Each research prompt draws card hand drawn will contain {{green|3}} research alternatives<ref name="defines" />. This may, however, be further increased with the following:
{{Bonus table|research alternatives}}
Additionally, some research options 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 or , from special projects or [[event]] chains. The These options will always appear as available options are then removed from the alternatives' draw pool when drawing a new card hand and will remain on the research list 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 expand.
As opposed to a permanent alternative, there is no guarantee that the technology in question would be available will appear in the following promptsnext card hand drawn.
== Research output ==