Backfill bug

Issue description

When backfilling rock (other marital untested) up against retaining wall crosses the material wont backfill properly. The dumping designation will indicate that an area is fully filled, even though there are holes big enough to alter pathfinding and construction.

Expected result: backfilled flat so that buildings and pathfinding can be constructed on top of backfill up to the edge of the retaining wall.

Reproduction steps

Reproduce: Load save file included. Go to zones under vehicle management and go to zone "Bug test". On the lose storage 3 filled with rock that has an export route set up to a mine control tower, tell trucks to empty and assign trucks to do the job. They will being backfill and leave gaps. (example circled in red in screenshot below.) Oddly, this bug seems to only occur on a specific axis on the map. (Clean axis circled in blue in screenshot below.) You can backfill other parts of that continues wall or look at other parts I have backfilled and find that it only happens on one axis.

Game version and build number

v0.7.4 (b441)

Operating system

Windows

Attachments

Bug Test.save

I'm not sure if this is related or not, but I've also observed some similarly odd behaviour with terrain on the flat 'connector' sides of retaining walls, like all 4 sided of the cross pieces, or the short sides of long retaining wall pieces. If a series of wall pieces are placed level with the ground (at +04 in these screenshots), and then dug around so that the terrain surrounding the walls are lower (e.g. screenshot)

and then the wall is deconstructed, the terrain will sort of 'stick' to the remaining adjacent walls

This makes it very difficult to 'lower' a retaining wall to accommodate changing terrain, because the terrain where the now-deconstructed wall was is still "at the previous height"

and forms a strangely steep angle of repose against that wall

looks to be 3/1 slope, whereas dirt usually seems to settle at about 1/1.

I'm not sure if it's related, but it seemed like it might be since it has to do with terrain heights and retaining wall connections.

Here's another screenshot showing even steeper 'sticky slopes' with both dirt and rock materials

So this occurred for me with the "correct" walls for the location as well. If I tell them to fill an area they think this is filled even though its not.

You know I think I saw that when I was playing earlier today too, I'll try to grab a screenshot next time I'm in game

Yeah, I'm seeing this now too.

Screenshot showing I can't build where the terrain is 'filled'

Even after deconstructing the adjacent retaining wall

I also tried deconstructing the diagonally adjacent retaining walls, and that still left a gap that "didn't need to be dumped" but I couldnt build on it (but I forgot to grab a screenshot.

However, I deleted the designation and re-designated it and now it will backfill