Did you check ArtifactImprovementDefs.xml? It is located in steamapps\common\Galactic Civilizations III\DLC\EXP4_Retribution\Game.

    <Stats>

      <EffectType>ManufacturingCost</EffectType>

      <Scope>Queue</Scope>

      <Target>

        <TargetType>Improvement</TargetType>

      </Target>

      <BonusType>Flat</BonusType>

      <Value>20</Value>

    </Stats>

This line controls the manufacturing/credits cost of an improvement.

    <Stats>

      <EffectType>Maintenance</EffectType>

      <Target>

        <TargetType>Improvement</TargetType>

      </Target>

      <BonusType>Flat</BonusType>

      <Value>1</Value>

    </Stats>

This controls the credits per turn maintenance.

You can learn a lot about modding by trying to add things to improvements/etc. by simply copying and pasting entries from similar structures you want to emulate. For example, go to ImprovementsDefs run a search for "Durantium" and you'll find a structure with the durantium cost. It's just a matter of experimentation.

Good luck.

So I've been working on this and I've gotten to a point of testing it, however, I can't seem to get the directories laid out correctly as nothing is changing either yes it worked or ending in horrible results, it's just doing nothing.

From what I understand the directory needs to match the game directory  So one creates ModFolder(with xml's in there).  That mod folder then needs to be laid out as the game folder.  So based on the game folder, I start creating sub folders in the (ModName) mod folder.

DLC ->EXP4_Retribution -> Game -> ArtifactImprovementsDefs.xml 

The one thing I don't understand is the ModdingReadme file says all mods must include ParticleScripDefs, Text, Core, Game.  I just copied the example Mod folder, which had those folders all in there.  There is nothing in those folders but they are there.  Am I missing something?

Thanks,

Thanks again Rhonin_the_wizard.  It appears to be reading it now, I'm crashing the game, but at least it appears to be reading it.  One other question does anyone know if Duration Projects can be edited on how they continue to work cost in the game?  Thanks.