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Advanced Tech' Tree Design - Part Two by Blackclove |
(April 99) |
A guide to designing advanced tech' trees, including side effects of various technologies, recursive trees, proper termination, and branch theory. |
Advanced Tech Tree Design : Part Two | ||
Now that we have covered the basics
of tech tree design, it is worthwhile to consider all of
the picky details that need to be taken care of when designing
tech trees and all of the neat special effects you can
achieve using advances. I am indebted to Leon Marrick for
much of the material presented here, especially the list of special
effects for various technologies. Throughout I will illustrate with the Invasion Earth Mini-Scenario. You will want to be ready to open up the main files with Notepad and get into the nitty-gritty details -- for this part even more than the previous one. |
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"Invasion Earth" Example | ||
Note: This is the same file as used in Part One. For this tutorial, I've created a new mini-scenario called Invasion Earth. I've included a units file, a basic rules file, a people file, cities file, and the pedia.txt file. It is a total war scenario featuring aliens invading Earth. The mini-scenario has two main features that interest us:
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Partially Divergent Tech Trees? | ||
The examples I have given so far
assume that your tech trees diverge totally. That is, all
of the technologies that are unique to a particular civilization
are along a branch derived directly from Once Removed.
For example, we assumed that all alien technologies are
in a tree built on Destroy Mankind. But what if you want many of your technologies to be shared by all civilizations? For example, you might want a scenario about France and England in the 19th century that involved most of the same technologies with just a few short branches where the tech trees diverge. You might want the French to have more opportunities to develop their army, for example, while the British have more nautical advances. |
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Short Divergent Trees | ||
Perhaps the simplest case is where you have a short branch that you want only a few civilizations to have. In Invasion Earth, both humans and aliens can develop the Plasma Weapons and Energy Harness advances. However, we want the Terminator advance to require Plasma Weapons, but we don't want the humans to be able to research it! So how to we restrict the Terminator advance, which is NOT in a separate tree for the aliens? By now you have probably guessed the solution, which I have sketched below.
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What I have done is simply
to insert Terminators as depending on Plasma Weapons, but
also make it depend on an advance that only the aliens can get.
You could even use Destroy Mankind directly rather than
tracing it through later technologies if you want.
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Same Technology in Separate Trees | ||
Another possible problem would be dealing with two totally separate trees that should lead to the same advance at some point. For example, in Invasion Earth I wanted both the humans and the aliens to be able to get Guerilla Warfare eventually. The reason was that at some point the aliens should be able to convert people to their cause through bribery, mind control and alien cults. What I did was leave Guerilla Warfare in the human-only tree, but I included an event (see the Invasion Earth events.txt file) that gives Guerilla Warfare to the aliens when they learn the Sympathizers technology. Technology #34 is Guerilla Warfare (you can figure it out by counting down the list, or you can just use the Fantastic Worlds Events editor and create a GiveTechnology event using the name of the tech and it will convert it to the number for you). ![]()
To make sure that the aliens don't start researching Modern Weapons from Guerilla Warfare, we simply use the trick from the previous section and make Modern Weapons require both Guerilla Warfare and Kick Alien Butt to research, effectively making Guerilla Warfare a dead-end tech that the aliens get as a bonus for researching Sympathizers.
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Same Technology in Separate Trees II: Recursive Trees | ||
This trick was first used in
the Master of Magic, Jr., scenario. A recursive tree is one
that turns back on itself. It means that one civilization begins
far down one of the branches of the technology tree, but
not necessarily far down all of them. For example, in Master
of Magic, you can eventually learn all of the types of magic,
but to do so requires extensive research. However, each
tribe starts with ONE of the branches of magic. This would
be a recursive tree, because at some point you get the
technology to move down other cultures' tech trees.
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Getting Closure: Future Tech | ||
The technology tree should be
possible to trace all the way to Future Tech or you may
run out of advances to research (which creates some problems).
However, if you have multiple branches that could be a
problem. The solution is simply to use GiveTechnology to
ensure that everyone can research future tech eventually. In Invasion Earth, the humans can take the direct path to Future Tech, as it depends on Energy Harness [Cst] and Edge of Tomorrow [Chi]. The aliens, on the other hand, can't ever reach Edge of Tomorrow. So what I did was include a GiveTechnology event that gives them the Edge of Tomorrow advance when they discover Adv. Alien Tech [Che]. Viola! They can now get Future Technology. |
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Special Effects | ||
Many technologies have game effects that are not obvious or not clearly documented, so you need to be careful about what advance you use for what purpose. I usually mark off a few of them with *'s right from the start to ensure that I don't mistakenly use one for one of my technologies by mistake. Here is a list of the special effects for various technologies, quoted directly from Leon Marrick's paper:
[Ed Note: Fundamentalism, The Republic, Monarchy likewise allow their respective government forms. See the page on Fantastic Worlds Advance Slot Properties]
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Tricks with People and Cities | ||
Notice that the Industrial cities and people appear only once you discover Industrialization, and Modern cities and people appear once you discover Electronics and Automobile. So, if you give players these technologies you can control what their cities and people look like. I did this with Invasion Earth. The humans have Automobile and Electronics (though under another name) and so their cities use the modern style and you see the modern human faces I put in to people.gif. The aliens don't have either of these techs or Industrialization, so they appear as aliens with alien cities. You may want to look at both of these art files to see what I did. People / citizen images may also be amended by providing 'Philosophy' and 'Invention' (or the advances in these two slots), in order to change from the Ancient to the Renaissance styles [Ed: Thanks to Ithil for highlighting this].
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Concluding Remarks: Part II of the Tutorial | ||
This part of the tutorial covers
tricks with the tech tree and has some thoughts on tech
trees that are partially interconnected. It finishes the main
part of the Advanced Tech Tree Tutorial. I may have a Part
III at some point covering branchiness theory, but it will
likely appear both here and on the upcoming Call to Power SLeague
area as it applies generally to any Civ-like game that
uses technology trees. Thanks and keep on Civin'! ![]()
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