Re: Is the Fluid Rework still planned?
Posted: Sun Feb 07, 2021 6:53 pm
.
I probably shouldn't humor you, because the issues are well-documented elsewhere, and your ignorance is showing.
Pipes are very expensive CPU-wise. Megafactory builds often try to avoid nuclear power because of the CPU burden of the fluid simulation that it adds. This is because a fairly complicated calculation needs to be performed on each pipe, whereas many other things can be optimized with timers and such in the implementation, avoiding much of the update cost.
The problem isn't that there's no way to optimize a fluid network, but that the game's mechanics seriously constrain what you do unless you want to over-build your junctions. Let's say that I want to distribute 1k fluid per second into a pile of assemblers making rocket fuel. In practice, this will require most of the throughput of a single pipeline. The tricky part is that I basically have to avoid intersections like the plague, or else I will end up with arbitrary bottlenecks due to game weirdness. That means the assemblers have to be arranged in a manifold configuration, unless I want to have an over-built pipe intersection to work around the bottlenecking issues, which is expensive in terms of pipes, space, and CPU.
When you are forced to build pipe junctions due to other design constraints, things get really awful. Because the behavior is inconsistent, I cannot predict how a particular junction is going to behave. Period. This makes efficient engineering basically impossible. Instead, I have to put worst-case bounds on the junction's predicted behavior based on the worst possible behavior that the system could throw at me, and this typically results in me building junctions between m and n pipes as m*n grids of pipe pieces, because that's the only thing that I can guarantee will work. If we had the alternate system that had been proposed and prototyped, we would be able to solve for steady-state behavior of pipe networks with ease - in fact, you could use tools like circuit solvers to do it for you.
For another example of how this fluid system makes life difficult, you cannot build factories that inherently maintain symmetric consumption/production when fluids are involved, because when fluid levels drop below what is required to maintain maximum throughput, junctions will behave asymmetrically. There are reasons that you might want to do this when interacting with certain train station designs, and it is easy to do with belt-only designs. Factories that handle fluids, on the other hand, now require belt balancers in order to work around the game's nonsensical fluid behaviors, which take up space and can get quite complicated when dealing with larger numbers of belts.