Disambiguation:
Belts going straight into buildings a la Satisfactory, Create in modded MC, or Mindustry. Buildings usually have slots that allow you to plug a belt into them.
Inserters/mechanical arms that take items off a belt and insert them into buildings like Factorio, or Dyson Sphere Program
My own thoughts:
Inserters and mechanical arms are generally a cleaner system since setting up assembly lines you just have belts running parallel to machines. The case for belts that directly go into/out of buildings is that it makes the math for throughout a lot simpler because there is only 1 rate in the distribution to worry about. Games where inserters have stacking, different speeds, variable throughput depending on destination, etc… have annoyed me a fair amount so I like the straightforwardness of having a belt that carries 120 items/min no matter what.
A pretty important thing to note is that 2d factory games are gonna struggle with a direct belt access mechanic since it means belts have to go through each other a lot, diagram below
[12] [12] [12]
-/|---/|---/|
--/----/----/
The belts in the 2nd line have to cut through the first. In 3D that’s not a problem since you can just stack the lines vertically instead, but in 2D you have to use whatever mechanic the game has to go above or below existing lines. I think this is the main reason the inserter mechanic is most common, but some games like Mindustry solved this problem neatly and allow you to easily pass items in multiple directions. Dyson Sphere Program also has direct belt inputs for a few buildings where only 1 input is needed, but DSP allows belts to easily cross over each other in 3D space, it just doesn’t allow stacking assemblers vertically like in other 3D games.
Another solution for 2D games with direct access belts is to allow for the building itself to act as a kind of junction. Final Factory (an underhyped new release) has this system where you run your belts like this:
[1]--[1]--[1]
[2]--[2]--[2]
And as a building fills up, it starts passing the overflow to the next one. This means as long as you feed the first building in the chain with enough items to stock the whole line, you’ll be fine. Then you can take the products out the bottom or sometimes you can fit another line through the crafters to take the output from the assembly line.
Also, another thing, some games use neither system because they rely on other systems for transporting items, like units that automatically carry them. I haven’t played any games like that outside of modded Minecraft with Thaumcraft golems and Pneumaticraft drones, so feel free to give your thoughts on those (I think Oddsparks works this way? Haven’t tried it yet).
I haven’t played Factorio in a while but it’s back in my backlog. But DSP does both but for different buildings and I can remember getting confused on how to feed silos or exchangers because I was coming from Factorio which does everything with inserters.
I don’t think I have a direct answer but I usually try to adapt to whatever system the game goes with and more care about what kind of quality of life stuff they offer. Maybe direct feed might worker better in DSP for dense intermediate parts factories but the player base also sort of answered the dense factories issue with belt bending. At the end of the day, for DSP at least since I’m a from raw player, I’d say inserter?
I don’t mind Satisfactory’direct insert as much as the FPS point of view. I wish you could go into 3rd person camera movement like in DSP. But that’s a whole other complaint lol.
Well DSP basically only has direct insert for tanks, distributor mounted chests, fractionators, turrets, ray receivers, logistics stations, and mining machines which I think is just because they aren’t grid aligned while inserters have to be grid aligned. I gotta say that the way DSP implements inserters is just nice since they tend to be balanced in a way that makes MK3 inserters good enough for all reasonable use cases. I think the annoying thing is in a game like Factorio where you need to use an array of inserters in some cases to get enough throughput.
I never even made the connection about the assemblers, smelters, and such needing to be grid-bound lol. I do still think it’s funny that they introduced stack inserters as their tier 4 inserter and it has basically replaced pilers since pilers tend to chew through UPS.
I think I get what you are saying about Factorio but it’s been years since I played it. I know even into super late game DSP, I still use blueprints that have yellow and green inserters and belts for balance though. (I’m lame and mostly use a bunch of blueprints form other players lol).
Pilers are pretty irrelevant in DSP thankfully because of the ILS upgrade to just always export items in piles. Best of both worlds that way.