Ever since I saw Factorio I wondered how is this little man hand crafting all those complicated and big structures? One solution I found is similar to how you make things in Subnautica. You start with Star Trek like replicator in your escape pod. Makes me think that Engineer has one in his backpack to make all the items. It does not consume any energy and can make items of any size.
My idea is to have Engineer inventory and his backpack device visible and upgradeable. Everything divided in number of slots for different extensions. Backpack itself is a bit of storage and a bit of crafting utility (like Subnautica replicator) and connect to each other. You can make small objects and components.
Slots:
Right/Left hand: One hand has generic Pick & Axe tool for early deforestation and raw ore gathering, Other hand later could be equipped with replicator gun (something like nano-bots gun from mod).
Chest: Conventional armor slot, more in a sense of bulletproof vest over standard uniform - in this case Power Armor would be an entity like a car/tank.
Head: Generic helmet with headlight, night vision googles, etc.
Belt: Batman style belt with everything you need that fits pockets. The current Factorio belt is more like a shortcut to inventory rather than real belt. Haven't really thought about it.
Backpack:
This is your inventory and replicator. They are connected and as such you can handcraft small things and structure components. It is very limited in what it can make, what can be stored inside (limited space so forget of stuffing whole rocket silo inside or 10k iron plates) and is slow at crafting anything above screw, bolt, small components in general. Think more on the realism.
If we keep with the start after crash landing theme then most of the items you start with are damaged and therefore even less effective. You would also need some kind of way to provide power to your backpack. Rechargeable batteries come to mind.
Speaking of crash landing. Is it possible to start with crashed space ship? It could contain some essential components and materials. Some form of weak power source (used to charge backpack replicator and few devices). If we look at it as chest with items then power source would be a damaged reactor.
Ship (more like escape pod or small shuttle at best - like the Star Trek ones) could also be an entity like buildings from Factorissimo with interior and things you can interact with. I'm thinking more and more Subnautica starting position but not as wet. If I went with this then having replicator in the backpack would not be all that important as the ship would fulfil that function just as well or even better, having more space to work with.
For Factorio Crashed ship instead of a chest could just be all in one: Assembler, power source, storage space, early research station etc.. You could later disassemble the the whole into components and materials or fix them and make the whole thing able to fly (saw a plane mod in one of the Youtuber videos) making it a mobile assembly machine.
I'm thinking along the lines that right after crash the reactor is too damaged to make the power from "fuel" or maybe too unstable to output the power at 100% to make the shuttle fly. Some other high tech components could also be missing. First stage of mobile assembly could in this case be battery powered Backpack replicator with particle gun (for larger structures), then a truck. Construction robots would be very advanced and most likely you would need more than one of them to assemble anything with reasonable speed.
With some power provided by Ship reactor you could remove/ignore burner miners on the other hand their complexity is low so they might be easier to start with (no access to electric engine technology or construction materials). Having ship with assembler first would also make hand crafting less of a chore. You could still assemble some items with hands but no longer twist and bend iron plates into gears.
Talk about components, assemble this, assemble that. I see some potential change in how you build things. Instead of clicking button and getting steam engine or assembly machine after some time you would need to put more effort into this.
First make everything more complex, needing more components. Instead of plates + gears + electric circuits make it be something like assembler frame (that comes from few other sub components), some internal box with gears, machine hand tools etc. (making ship assembler very important at the start). Electric miners would have frame, some gears, complex bits and some kind of mining head (that could for the most masochistic of people have durability and need replacing from time to time). Electric engines could be opened earlier and be made from different materials - also a complex bunch of stuff. Even conveyor belts could be made more complex.
Building the base: Since everything is more realistic and bigger just running around and slapping buildings left, right, centre is a no-no. What you are placing in this case is "construction site" - a blueprint/ghost image of a desired structure that has inventory. You put the items it asks inside and then magic happens. You either stand near and hold button to assemble the parts or spray the thing with ship or hand replicator gun (or some other mobile version of replicator). Again character inventory would be tiny so maybe the largest of parts could take the hand slots as in - you carry the item in your hands.
Replicator guns would have limited range depending on their size and power.
How will my army of robots build my base for me you ask? Construction robots have on their board weak replicator gun or maybe something near the level of hand gun. They will fly to the construction sites that have all the materials and assemble the structure. Most of the time group of construction will move to assemble things to speed up the process.
You also wont need to hand place all the materials on construction site. I have 3 options: Logistic robots place do it, Construction robots go into transport mode and put the things in and finally dedicated transportation robots (can look like blimp) make the effort.
Next after assemblers and other replicator like entities are prefabrication plants. They make the going big possible, building huge base is no longer a dream. You place orders in them of what "finished" things you want, like miners or assemblers. This plant works like a virtual construction zone. They make ready to place buildings (some size limitation is in place - no rocket silos in boxes). Then when you paste desired buildings blueprint somewhere on the map, transport robot (it a cargo blimp) takes pre-made entity and places it on site. Construction robots finalise the construction process.
This sadly makes removing buildings a difficult task. If you can repack them and move somewhere else with transport robot then fine, but early on it would lead to lots of reassembling and rage. Moving construction zones is not a problem. You would need to be 100% sure that this is where you want stuff placed before assembling it.
Again since you crashed most of the things are damaged, destroyed, can be salvaged for components and lastly fixed to get 100% efficiency & new functions. You could also choose to start by landing on the planet instead of crashing for easier game
Last minute change: Having flying ship you could also set up landing pads around your base for automated transportation. There was another thing in my mind about this functionality but I forgot what it was. ~edit2: In case of crashed shuttle technologies would not be researched but salvaged from it's computer data banks (that we try to fix with science potions or some other mechanics).
HUH... This is it. Was going to be only about Engineer and his backpack of wonders and look how long it came out
