Yes, that's right, the tech tree the game displays (and that you can find handily on the front page
of this site) is incomplete... MAJORLY! So here is the completed tech tree.

WARNING: I suck at art, so this isn't the prettiest thing. All I did was add lines to the existing
graphic. RED lines depict a link present in the XML file that is technically not needed and could
be removed, because the tech's prereqs already have this as a prereq, making it redundantly
unneeded so you don't need it. :D

ALSO, I couldn't figure out how to get it to display this in game, so if someone has that information,
please post it.

And now, the pic.

Firsty, I hate to say it, but the red lines are wrong. The arrows represent "OR" techs, and as, for example, you can get drama without meditation, there is no redundancy.

Secondly, the tech tree isn't static, but instead generated dynamically by a python script when you start the game, therefore you'd need to mess with the python file instead.

I used to consult here (http://www.civfanatics.com/civ4/techtree/index2.php)

Pretty pretty colors!

Er, anyway, uh... dynamically? Holy guacamole! But then that leads to the question of: why in the world, if the tech tree isn't the same each time, doesn't the game also dynamically draw the lines as they are needed? Instead, I try to research Monotheism after I've got Mysticism, thinking I need Polytheism first but not Masonry, and it wants me to research Masonry as well. So why wasn't there a line telling me I needed it? What's the point of clicking on "big picture" (and for once, they take that literally) if you don't get to see what's really going on?

I'm not blaming you, of course, but you seem to have a better grasp of this than I'm having, so I would welcome your input.

Here's an image to help you.

Yechh! That didn't come out right at all.
Okay, basically the techs shown on the right-hand corners are "AND" techs:
You need those no matter what.
The techs with arrows leading from them are "OR" techs:
These you can mix and match however you want.

I always thought it was a little backwards ("AND" techs should have arrows, not "OR" ones). Which brings up another question: If the tech tree is drawn up from a script, how hard would it be to reverse the arrows in Python?

I always thought it was a little backwards ("AND" techs should have arrows, not "OR" ones).

IMHO the current representation helps us to plan beelining path based on current requirement. For example, if it was shown like your proposal, it will be more difficult to determine that the fastest route to music is through mysticism(50), polytheism(100), priesthood(60), writing(120), alphabet(300), literature(200), and mathematics(250).

RED lines depict a link present in the XML file that is technically not needed and could be removed

Removing your red path is misleading. For example, if it was removed, then people would think that philosophy can be reached through polytheism-priesthood route, without needing meditation.

About dynamic techtree, it's the same old tree in all the game I've played. But may be if someone modify an xml file that dictate the requirement of some tech, the code that draw the tree could re-route some its arrow accordingly.

I and some others created a reference guide including a tech tree. Please take a look here (http://forums.civfanatics.com/showpost.php?p=3561293&postcount=45).

I'm still thinking of reordering the boxes to match up with the techtree ingame, but you know..... time ;) .

I also thought of doing this ingame, through pyton, but after finding the correct file to edit I didn't know where to start.:crazyeye:

The red lines may not be entirely correct, there actually is one line that should be red. And that is the connection Nationalism - Fascism. It is useless, since you'll have Nationalism from Constitution-Corporation-Assembly Line-Fascism.

As someone creating a completely new tech tree for a mod, the fact that "or" techs create lines but "and" techs don't give me some flexibility when trying to lay out a legible mod. For example, if a line between two techs would create spaghetti, I can make it an "and" tech and not have the line show up. This is a problem when I really do want to have "or" techs because I don't have that choice -- and since there are more "or" than "and" options, almost by definition, I have to say it is a little weird that it's the "or" techs that get the line. But, whatever.

It probl;ably was the only way they could make the standard tech tree or something