Cargo lifts and hopper permissions...

[Robert]

I've just learned something new about the behavior of cargo lifts:

Since you should upcraft ore to bars as soon as possible (especially on higher difficulties where you need up to 16 bars per ore instead of just 2-4), I made it a habit to place smelters right next to the hoppers the lift unloads into: Lift->Hopper (remove only)->Smelter->Hopper (add only)->Conveyor->...

Which usally works fine, but one of my lifts was acting up, only one of the 3 attached smelters was producing bars. And now I understand why: One of the lift hoppers was set to "add+remove" instead of "remove only". After playing around with that a bit the rule seems to be:

A cargo lift will unload into hoppers set to "remove only" - but only if there is no other hopper next to the lift which has other permissions (add only, add+remove). If there is, the lift will ONLY unload to those hoppers and ignore the ones set to "remove only", even if the other ones are full! Probably similar rules apply to loading lifts, I didn't test that yet.

I wouldn't call it a bug, maybe a little design flaw or an undocumented behavior or something. Ultimately it's just a rule which makes sense, but I wasn't aware of it so far. Now that I understand this behavior, everything is alright. Just wanted to drop this here in case somebody else is wondering why their similar solution behaves in a weird way and searches the forum for info about it.

[Chris]

Nice tip (;

[Robert]

Just got an idea, but no clue if it works: assuming you have "add only" and "remove only" hoppers on the same lift, and assuming that the lift will only unload into the "add only" hoppers, but load from the "remove only" hoppers... that would allow to use the same lift to bring ore up and cutter heads down. That would be pretty cool, right? Transport pipes are expensive, and a dedicated lift just for cutter heads is kinda overkill (been doing that in my old world).

Maybe that's something obvious which everybody except me already uses in their fortress though lol.

[MyProfile]

Add, remove and add and remove are the most confusing terms and behaviors used in this game.
It depends where your standing as to what it means when you're trying to figure out which is correct to use. If I were to change anything that would be the first thing but I guess it makes perfect sense to some so just leave it like it is... Confusing.

I have to ask though, what would be wrong with, input - output?

[Chris]

Yes, the hopper permission system is extrem difficult to master. You can not feed a machine over one hopper and get the result in a diffrent one, without this settings. But hen you caan not place a falcon to offload into the input hopper. So you need to have a belt betwean the hoppers to feed a turbine over a falcon. Everyone knows the problems....
Directional hoppers are sometime the solution.

For Cutterheads: You will learn more fast as slow, that this is a realy bad idear. You need cutter heads at different location hights. You only need 1-2.
The best way for cutterheads are Mattermover. Use a white laster and it is still working. It is simply working and proofed.

[Robert]

Originally posted by Chris:

For Cutterheads: You will learn more fast as slow, that this is a realy bad idear. You need cutter heads at different location hights. You only need 1-2.
The best way for cutterheads are Mattermover. Use a white laster and it is still working. It is simply working and proofed.

You're probably right there, and that's what I've been doing in my last world. I started with transport pipes, then didn't like that hundreds of cutter heads are always "on the way" to their destination, so I replaced most of them with matter movers. Although... the cutter heads are produced on the surface, which is where the cargo lifts are too. And each lift goes to the depth where that specific ore is. But the problem might be the lift settings themselves, I didn'T try it out. What I mean is, you set the lift to "unload at the top", for example. So, will that lift even try to grab stuff from "remove only" hoppers from the top? Probably not...

[LeDuck]

I'd be concerned about a two-way lift carrying ore and cutter heads getting completely filled w/ cutter heads and deadlocking the system.

The lifts don't have configurable limits (at least not the vanilla ones, someone has probably made a mod that does that).

As mentioned earlier, matter mover's seem to be the best way to move cutter heads.

To share another method tried - At one point I converted all my ore ransport to use exclusively minecarts: no lifts or belts with a length > 5, and setup a matter mover delivery station for each extractor. Everything seemed fine at first: the extractors got the cutter heads and were doing fine. Until a few savegame loads later, when the network started to clog up with minecarts carrying cutter heads blocking the mainline due to the way minecarts function across game reloads.

[Robert]

Yeah. The current lifts just aren't designed to work two ways automatically. You'd need a combination of "load all from the bottom" + "unload all at the top" + "load any from the top" + unload all at the bottom". Which obviously isn't supported by the available options.