I've looked all over and only found contradictory information on how Invasion works. From my experience, sometimes adding more invasion power has an effect, and sometimes it doesn't. In one of my games having more than one invasion fleet had no effect, but in others it makes a big difference. The wiki says that invasion is based on Military power which doesn't make sense at all.



Can someone just give me the formula?

The Wiki is consistent with Base Endless Space in regards to Invasion.

In Disharmony, you compare Invasion Strength versus Defense Strength. The formula is something like Invasion/Defense. That amount is lost from the system control each turn. It is capped at a maximum of ~13% loss per turn(I think, it has been changed a few times in the recent patches).



Bombs destroy either population or buildings (depending on the type), either reduces system defense. You need bombers (or invasion/combo fighters) to use bombs.

Troops can immediately take over a system, but you need to replenish them after use either by refitting or normal healing (10 or so turns, depending on repair modules). Systems taken over by troops are generally devastated by the attack and have few if any buildings left. When you build troops, they consume a population from the system you build them from, just like colony ships.



The general siege advice is:

• Build 1 ship design with all siege modules
• Build 1 ship design with max troop modules and the remainder is siege.
• Use whichever you want, build more as necessary. Combine them in siege only fleets.
  
  

I've never bothered with bombs, but I guess if you want to weaken a system, they would work. I generally just build more siege ships or use troops straight up.

Mhh i wondering how exactly the formula is which shows you the probability of an troop invasion success

No idea on that one. Troop, Bomber, and Invasion Fighters do have a ground combat strength. I've always gone with the plan of use lots of troops.

in all of the invasions i launched in disharmony, my troop success possibility was always 100 percent. on all of those occasions, i had fighters and bombers but no system bombing. i don't know if this is because the ai doesn't build defensive buildings though.