Question1: I see the game keeps the old tech trees are they still used?
When I want to set a requirement for an improvement for Terrans should I refer to MasterEnvironmentalResequencing or TerranEnvironmentalResequencing?
Question2: When I filter by ability I still see the same tree only for certain race, so if I make changes in the MasterTree e.g. the cost of a tech or the order in the tree, the changes are lmited to that race or the applied to entire MasterTree?
Q1: The old tech trees are in the game for those who do not have crusade. They need the old filestructure. Maybe the files will be removed in the crusade version. We have lots of files duplicated and right now its a big mess. I think stardock will fix this with a patch soon. So if you use Crusade, forget about the old trees. You need only the the MasterTree. IF you want to have Race Specific Tech, means unique to just one race, you need to create the Ability, for example "Terran" in the AbilityDefs.xml and you have to create the new techs in the master tree with the addition
Q2: Techs are not anymore connected to a specific race. In crusade, races have specific abilities and this creates a different tech tree. Means if two races share the same abilities, they have the same tech tree. So every change in the MasterTree on a tech, will affect any race, who is able to use that specific tech. To make things a bit more comlicated, you can also mark some techs to be unusable for some races with certain abilities.
would mean, this tech wont be available for races with the ability Sinthetic Life and Silicon based Life.
Hope this helps a bit.