Editing Technology tree (section)

===Prerequisites for technology advances===
In most types of strategy games, the player needs particular buildings in order to research specific technologies or build specific advanced units (''[[StarCraft]]'', ''[[Total Annihilation]]''), while in other games upgrades/technologies are unlocked through research alone (''[[Warzone 2100]]''). In many TBS games the prerequisite is one or more lower-level technologies, with no dependency on specific buildings (''[[Master of Orion]]'' series, ''[[Civilization (computer game)|Civilization]]'' series, ''[[Space Empires]]'' series).<ref name="SeeGameManuals">See the relevant games' manuals.</ref><ref>''[[Master of Orion]]'' (1993), the ''[[Galactic Civilizations]]'' series and ''[[Sword of the Stars]]'' have no research buildings; players simply allocate some of each colony's output to research (see game manuals). In the ''[[Civilization (series)|Civilization]]'' series (1991 onwards) and ''[[Master of Orion II]]'' (1996) one can do research without buildings, but it's much faster when supported by the right buildings (see game manuals). In the ''[[Space Empires]]'' series (1993 onwards) and in ''[[Ascendancy (computer game)|Ascendancy]]'' (1995) research can only be done via buildings, but these can research any technology (see game manuals).</ref><ref name="RakrentRTSBasicsRnD">{{ cite web | url=http://www.rakrent.com/rtsc/rtsc_rnd.htm | title=RTS Basics: R & D }} and the ''[[StarCraft]]'' manual. Although multi-epoch games like the ''[[Age of Empires]]'' and ''[[Empire Earth]]'' series have a larger number of research options and a significant proportion of civilian research options, the research options all depend on having the right buildings. See the relevant games' manuals.</ref>