So, I'm trying to design a good factory floor before I get all into things - I've gotten frustrated with trying to get an Arc Furnace running, might want to consider a different, less efficient way to purify ore. Having the ore processor seems like it would fit - The arc furnace advantage is it's automatic.
I'm looking at the Minecart loader, and you say in the manual that it loads items on TOP of the loader ie. 9 squares. This is kinda irritating, because I can't think of a way to get items onto it without using an intervening dwarf - it can't share the same space as an output tile. This kills my idea of a safe, separate factory floor that my gnomes never step into unless it's to change settings.
A couple more things: What happens to the stone in the Arc Furnace? The ore processor separates the ore into pure ore and stone, i believe, though at what ratio I don't know. Assuming it just gets rid of it, couldn't you add a second output to the arc furnace that pushes out the stone?
Also, is it possible to have two (or three) inputs to one factory? That would make tightly packed machines easier to arrange.
I'm loving this mod! Personally, I don't really care about my druid score - I just want to automate everything! I can do that as long as I ignore the animal training areas, right, using only clockwork? Also, if the Arc Furnace incinerates all invaders, would one or two input tiles connected to furnaces completely destroy any invasion, regardless of trap evasion/armor? Not that that's a change from normal dwarf fortress, lol, but would invaders even react to the troops ahead of them getting sucked into giant fiery machines of death?
Finally, if I wanted to try adding workshops from Masterwork into Gnome, how would I go about doing that? I'm assuming the lack of stonecrafter shops is intentional, but it makes getting some of the trap components much harder to get, since you need a working furnace, so I'd like to add it in, see if it makes things too easy.
Okay, first off: items produced by factories are not placed onto the output tile itself - they are placed on the empty space OPPOSITE the output tile (think of the machine output building as a pipe leading out of the factory it is connected to). This means that you can chain factories together by placing an input tile for a second machine in that empty spot: see the diagram in the manual. The minecart loader is actually single tile building; it's main function is to do exactly what you suggested, to make a factory area where the input and the output are both handled entirely by automatic minecart systems.
So basically, you'd have the following setup: Factory -> Output -> Minecart loader -> Minecart track.
You can have as many inputs or outputs for a factory as you want. If there are multiple outputs, items will be distributed at random. Multiple inputs for the item sorter will make the sorting function not work, but it can still be used to combine two separate assembly lines. Also, when planning a design, don't forget you can power factories using gear assemblies below their center or corner tiles. This is important if you want to create a large factory room - I almost never power factories from the side, despite the diagrams in the manual (that's just to make it clear that each machine must have a power source.)
Every machine works by 'ticking' at certain timed intervals. During a 'tick', the machine will process items it has inside it, pull in an item (or creature) from the outside, place an item onto an adjacent minecart, or do whatever else it is the machine is designed to do. Directing more power to the machine makes it 'tick' more frequently.
Because of this, even with a properly positioned minecart loader, it is very difficult to load items into a moving cart. You have to either make a system that stops and starts the cart while it is adjacent to the loader, pump a huge amount of power into the loader, or simply wait until you get lucky enough to have the loader's 'tick' coincide with the moment the cart passes.
This is also the reason why relying on factories for defense is not as game-breaking as it might seem. Although trap evasion, defense, or even the TRAPAVOID tag aren't taken into account, a factory will only kill a creature if it happens to be standing on top of it at the moment it 'ticks', and even then only if it doesn't have any other items on top of it (such as pieces of the last invader to walk into it). Also, because of the shape of factories, it isn't possible to make a tightly-packed trap corridor using them. At most, you can make a one-tile-wide path leading into a single machine input tile, but that won't be very effective against large groups of tightly-packed invaders. Using cart loaders as traps is even more difficult, as it requires the invader AND the minecart to both be in the correct position at the moment the loader ticks... but it's very rewarding if you can pull it off (Endless Rollercoaster of Doom!)
Or you could try leading enemies into an Aerial Transport Device that launches them back toward their own allies. But on the whole, while there's more potential for fun, factories just aren't as effective a defense as a good old fashioned trap corridor.
The output of an arc furnace is identical to that of the ore processor and metallurgist combined, i.e. it separates ore into stone boulders (occasionally blocks), metal bars, and slag. Non-ore stone items placed into it come out completely unaffected (as of a recent update). This is important if you want to create a factory that processes both ordinary stone and ore, since item sorters can't separate the two (unless you have a sorter for every kind of ore). You can easily deal with stone by feeding all kinds of stone into the arc furnace, connecting the arc furnace's output to an item sorter that removes all bars, and sending the remainder towards a stone cutter and furniture assembler while the bars go on to the forge.
The lack of stonecrafter shops is intentional: the stonecutter machine produces 16 blocks from each boulder (as opposed to the mason's 4), and the furniture assembler requires 5 blocks for most large furniture items. This is more efficient than the dwarf version once you get the infrastructure set up (about 3 items per boulder instead of 2) but if you were to add in the stonecrafter, which uses only 2 blocks for most items, you'd be able to turn each boulder into 8 items...kind of pushing the limit there. Don't forget, most trap components can be made out of wood in the Carpenter's Workshop (including mechanical arms). You'll need to get metal from the vanilla smelter to create a sawblade, but you can easily have a stonecutter/furniture maker combo pumping out stone items within your first season, especially if you bring some copper and anthracite with you.
You don't have to worry about your druid score if you're not planning on using the nature shrine or advanced animal training.