[0.17.43] Inserters changing distance only affects speed when dropoff is farther away

[alercah]

It's possible, with mods, to create inserters that pick up and drop off at different distances, such as picking up from one tile away but dropping off from two tiles away. Bob's adjustable inserters are what I use for control over this.

Changes to position that inserters need to do generally take time as the head repositions itself. But oddly, inserters seem able to retract for free while rotating, but not extend.

To see this, load the attached "offsets" save (requires bob's inserters, angel's warehouses, and creative mode). Drop down a power source in range of the substation to turn all the inserters on.

The leftmost inserter picks up at distance 1 and drops off at distance 2. The middle inserter drops off and picks up at distance 1. The rightmost inserter picks up at distance 2 and drops off at distance 1.

You would expect that the two outside inserters, which both need to adjust distance by 1 tile between picking the item up and dropping it off, and then do the reverse between dropping the item off and picking the next item up, would take the same amount of time. The operations of "extend 1 tile" and "retract 1 tile" both exist on each of the inserters and must be fit into the other operations somehow. Furthermore, if extending and retracting take any time at all that can't be just mixed into inserter rotation, then you would expect further that they would be slower than the inserter without extending and retracting.

Yet, instead, the rightmost inserter operates with the same speed as the middle inserter, meaning that retracting after picking items up, and extending after setting items down, is free. At the same time, however, the leftmost inserter is slower, meaning that extending after picking items up and retracting after setting items down does take more time. It is very inconsistent that the time should depend on where the extension/retraction is relative to pickup/dropoff.

Looking at the visuals, it appears that the rightmost inserter is able to extend and retract during rotation as needed. But the leftmost inserter, for some reason, cannot extend or retract as quickly and must spend some ticks doing so even after the rotation is complete.

This does not appear to relate to rotational direction (i.e. if extending while rotating one direction was faster than while rotating the other), as you can see in the "offsets-opposite" save. In this one, both are extending while rotating in opposite directions; if rotation direction was responsible for the discrepancies, then you would expect to see this reflected in a difference of speed here. Instead, it seems purely related to whether extraction happens before or after dropoff.

[alercah]

Update: it also seems to require rotation; simply extending and retracting doesn't suffer the speed difference as seen in this save.

[Twinsen]

This is more of a modding request or a minor issue, so i moved it to "Modding interface requests".