- If I set "manual control" in the empire policies, then I need to upgrade every design myself, both private and state. The "automatically upgrade design" serves no purpose.
- If I I give control over vessel designs in the empire policies, all designs are fully automated by default.
More or less, though it remembers the settings from your last game or your current settings in this game. So if you set destroyers and cruisers to manual design last game, and then started this game with ship design on 'control manually' but later switch it over to 'fully automate,' destroyers and cruisers will start out on the manual design setting unless you switched them to automatic designs at some point during the current game.
- If I want to have control over a specifc type, then I disable "automatically upgrade design", which renders me responsible of keeping it up to date.
Yes, though remember that this affects all designs within a given ship role. You cannot have two destroyer designs, one of which is kept up to date automatically by the computer and the other which is kept up to date by your intervention. You can have two destroyer designs where both are kept up to date automatically by the computer, and you can have two destroyer designs which are both updated by you.
- E.g. I disable automatical upgrade for Destroyers, the AI will not create any other destoryer class nor upgrade the existing designs
- If press the "auto upgrade design" of a type I control manually, will all components be replaced with recent ones, but no new will be added? Or will the AI refresh the whole design as it assumes to be valid, i.e. add components which were not there initially?
My understanding is that this is how the button which asks the computer to automatically upgrade a design works. However, I've never played with that button, so I cannot say with any real certainty that this is what that button does.
- What does the "auto retrofit" in the design settings do? As far as I understand it only enables me to quickly retrofit to the latest design by clicking the small botton on the unit window. Any other function?
Auto retrofit tells the computer that it can assign your ships retrofit missions (if they or their fleet is automated) when you come up with a new design for your ships, without you having to go through your fleet and manually issue retrofit orders to all the automated vessels in your navy. I don't know whether or not auto retrofit acts like the fleet order 'retrofit to latest designs' or if it acts like the ship order 'retrofit to design X,' where X is the most recent mark level of whichever specific design that the ship currently uses. If it's the former, then it would make it a little more difficult to maintain two or more current designs in a given role when using automated vessels or automated fleets, as the computer would eventually order all your automated vessels to retrofit to the most recently created design within the appropriate role, whether or not it's the most recently created iteration of the specific class within that role.
I have one more question to add - assuming ship design is automatic, if I jump in and modify a design (e.g. add a component to all medium space ports) and then allow continued automation/upgrading - will the AI use that as a baseline, or will it remove the component I added in future updates to get closer to its optimum design?
If you take an automatically created design and modify it, and allow the computer to continue to have control over that particular design, then the computer will 'upgrade' the design back to whatever it had been doing, often shortly after you create your modified design, though it may preserve elements of your modifications which are not too far off from the design template. If you want automated designs to go to designs that you think are good, then you need to work out how to modify the design templates for the species you're playing, and if you want to do that I'd suggest looking around in the modding forum.
Basically, if your faction's default destroyer design uses railguns and missiles, and you modify the destroyer to use blasters, you can expect the computer to redesign your destroyers to use railguns and missiles soon after you complete your redesign. If you modify the destroyer to slightly change the balance of railguns to missiles and be a little bit faster, then there's a fair chance that the computer will let the design be for a while, since your redesign still approximates the 'ideal' design set by the design template.