Factorio Forums

This often happens to me in the Speedruns, when i tripple belt while running:

If you move your mouse very fast while placing belt, you will skip some blocks and only have 2 placement samples that are not adjacent. Usually the game fills all blocks in between those 2 samples with belt, so you don't end up with gap between you dragged belts.
However, if there is an entity in between, the algorithm may not fill, even if it is a belt of the wanted direction

Ascii art examples:
_ is free block
< is Belt
1, 2 ,3 , .. is mouse Position on Tick 1, 2, 3, .. (while holding down placing)

1: correct behavior
Before:
>>>>>>____1____2____3
After:
>>>>>>____>>>>>>>>>>>>

2: starting dragging on a Belt:
Before:
>>>>>>1>>___2_____3
After:
>>>>>>>>>-___>>>>>>>
correct result should be:
>>>>>>>>>>>>>>>>>>>

3: dragging over an already placed Belt:
Before:
>>>>>>2>>______1
>>>>>>3>>______4______5
After:
>>>>>>>>>>>>>>>>>
>>>>>>>>>______>>>>>>>>>
correct result should be:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>


Video:
https://clips.twitch.tv/WittyCrackyJellyfishTF2John

Hi,
Great that you play go!
Yes, I see the problem. Unfortunately with the way the building code works this would be very difficult to fix. The mechanism is triggered when you build something, but when you don't, like when the tile is already taken by another belt, it is a very different situation.
Moreover, this auto filling feature has history of creating many bugs and is just better without getting even more complicated.
So it is fixable, but really low priority now. Sorry