Factorio Forums

What did you do?

Built an underground express belt going east to west.
Made a copy of that UG belt (including both end) by selecting the copy tool from the toolbar
I rotated it 180 degrees (pressed r twice) and pasted it directly on top of the original (left mouse click, no shift).

What happened?
When I hover the paste over the original belt everything is blue but the belt has switched to its orig direction.
Paste appeared to succeed,with no error message.
But in reality the belt was still facing the original direction.

What did you expect to happen instead? It might be obvious to you, but do it anyway!
I expected an "express underground belt is in the way" message.
This would be consistent with how normal belts and splitters work.

Write down the steps to reproduce the bug if you know them.
See above

Does it happen always, once, or sometimes?
always

Be precise! When i click with the mouse on Quit in the main menu... Not: When I close the game.

It looks like only part of UB that is considered for collision check is "ub mouth direction", but not "enter/exit state". underground belt rotated 180 degrees will have its left "mouth" pointing left and right pointing right - in that sense, there is no collision that would require "express underground belt is in the way" alert, but enter/exit will not change direction when applying blueprint
Possible solutions:
1/ include "enter/exit" state in collision check
2/ OR when applying blueprint, change direction of UB

Due to behavior with plain belts, solution 1 is expected

Thanks for the report. I don't consider this worth changing due to how fragile underground belts are when it comes to build-ability rules/logic. Not to say it won't ever change but right now it's just not important to us.