A common setup: 2 quantum gateways, with hives in between. The gateways make RAS SACUs. The hives assist both of the gateways, alternating between them. This way, the hives are almost always active.
If there was only 1 gateway, during the "roll-off time," the hives would be idle, so you would not able to use all that build power as efficiently.
But what if you are not Cybran? Can you achieve the same thing, with normal engineers? You can, actually.
You can get engineers to behave this way (alternating between supporting 2 quantum gateways) simply by placing an "assist" order on the ground near the gateways.
You can see this in replay #12819570
I selected all of the engineers and gave them a single (shared) assist order that was placed on the ground near the 2 gateways. At first, about half supported the left and half supported the right. Soon after, they synchronized and began alternating between left and right.
In replay #12819438 I did something a little more complicated. I picked a "lead" engineer who had an assist order on the ground. The other engineers all assisted this lead engineer. That guaranteed that all of them only ever supported one gateway at a time (whichever one the lead engineer decided to assist).
I suppose you could also use this technique, if you planted some engineers between 2-4 factories, and gave an assist order on the ground, they would alternate between supporting different factories rather than being idle during roll-off time (if they were ordered to assist just 1 factory). Which could help to more efficiently produce units, especially at the t2/t3 stage.
Would patrol do the same function between the gateways?
@Mvk_ "Would patrol do the same function between the gateways?"
No, it's not the same. On a patrol order, the units move around more. I think the issue is: on an assist order, they are willing to assist something within their maximum build range. But on a patrol order, some of them want to move closer to a factory before they begin assisting it.
Replay #12819836 shows what happens with patrol. You can see there is a significant amount of walking.
This walking also results in the engineers assisting both factories at the same time, instead of alternating between them.
I gotta try this. I assume it works for any kind of factory?
@Whatsisname "Or shift-g?"
In Replay #12819902 I used shift-g. You can fast forward to about 3:30 to see what happens. Shift-g doesn't help at all. What you end up with is half of the engineers are only assisting the left factory and half of the engineers are only assisting the right factory. So it doesn't help at all.
"I gotta try this. I assume it works for any kind of factory?"
Yes, an engineer that has an assist-ground order will assist any kind of factory within a certain range. I think the range might be "within a distance from the assist order equal to the engineer's guard radius" or double the guard radius, or something along those lines. They will also assist with finishing buildings that are under construction and assist with other things like loading TMLs or repairing units.
I'm pretty sure that engineers on patrol order will assist whatever they have in range only if your mass bar is almost full (maybe 3/4 full?).
I'm not certain, I'll have to mess around with both.
I just know using patrol with engines is nice in a base for various reasons at once.
Excellent piece of science. Unfortunately the effect this knowledge has on rating is negligible.