Factorio Forums

When using the smart belt rotation feature, the belt may sometimes face backwards.


It's a bug that has been around for a long time, so I hope you are able to fix it with this replay. I hear several Speedrunners are running into this Glitch frequently, so it's probably related to some fast, frame perfect input. Some say it may have something to do with overshooting.

Here is the replay with the bug occurring at the very end of it.

Here's another replay (22 minutes) where it happens right near the end (>80% of the replay) as I'm expanding copper furnaces from 10 to 24.

You can't see the cursor in the replay but it looks like my cursor may have been below the horizontal belt before I dragged it up. Also note that I was dragging it in the reverse direction (the belt should go down then left).

AntiElitz doesn't have the extra belt at the corner so my example may not be related. Unless he's right on the edge of the tile and it's not quite far enough to place the belt but it does set the direction incorrectly.

Yeah your replay is not related to my bug. Actually yours is not a bug, you just drag towards the wrong direction and don't have any undergrounds - so it places none.

I also get this a lot and it is quite infuriating.

What exactly did you do when that happened? Is that about the "smart rotation" feature where you press R to rotate the belts towards the mouse?
Since I can't see the cursor during playback, are your sure your mouse was on the right side when that happened?

If it was on the other side, there would be a belt logically. Replay has all infos though.

Just saw the bug on stream, adding as video showing cursor might be helpful https://clips.twitch.tv/FunnyFancyFungu ... eWlKLtmxRa

This still happens very frequently to me. Like once per hour.
Here is a recent example:
https://clips.twitch.tv/HotTenderCroque ... svDM54ItPk

This is something that annoys the hell out of me (when dragging belts, I'm encountering this certainly more than once an hour, more like once every 10 belts that I'm dragging), though I don't think it's a bug - more like a missing feature. I'll try to explain what's actually happening when the problem occurs.

1. When you're dragging a belt and keep your cursor exactly on the belt, everything works fine, even when dragging around a corner:
   https://imgur.com/a/f6Vq7fI
   (note how my cursor is exactly in line with the belt)
2. But of course, when you're dragging straight belts, you don't *have* to keep your cursor exactly on the belt - you still get a straight line even if your cursor is straying off the straight line:
   https://imgur.com/a/JkklVbF
   (note how my cursor is straying to the left for the second belt, and to the right for the third belt)
   So in practice, people usually won't bother keeping their cursor on the belt, because here it doesn't really matter.
3. When you drag around a corner, and your cursor is straying to the side where you want your belt to go, it still works out as expected:
   https://imgur.com/a/idrNUsN
   (note how my cursor is straying to the left for the first belt, and to the right for my second belt)
4. But when you drag around a corner, and your cursor is straying to the *other* side where you don't want your belt to go, the belt is placed in the wrong direction:
   https://imgur.com/a/EX1vyFV
   (note how my cursor is straying a single tile to the left before I'm pressing R and dragging it to the right)
   Though in this case it's still kinda obvious what's happening here, because the belt that goes in the wrong direction starts in the tile where my cursor was straying initially.
5. But if you do that motion fast enough, you will get the belt placed in the wrong direction, without it starting in the tile where your cursor strayed:
   https://imgur.com/a/WtDV2tY
   This is probably the point where people don't actually realize that their cursor was straying a tiny bit in the wrong direction, and wonder "why does Factorio place the belt in the wrong direction?!".

IMO what's necessary here is cleverer implementation of smart belt dragging. It shouldn't decide the final belt direction as soon as the cursor has moved from the first tile to the second, but instead should decide the final belt direction only when placing the last tile (ie after pressing R, or after letting the mouse button go).