Tank path finding problem - drives to water and becomes immobilized

[SlowMotion]

I'm playing a scenario called UK Armored Assault. CMSF 2.03.

I discovered a very strange tank path finding problem.
The path I plotted told tanks to drive near the canal edge, to same direction as the canal goes. This is shown in the picture as blue line.
What happened was that tanks drove down to canal and got stuck. Currently one is immobilized and the other is just temporarily bogged.

So the weird thing is: my order was not to cross the canal, but just drive along it. And these 2 tanks decided to drive to the worst possible place and now I'm about to lose them because of this bug.  Any ideas?

To see  if this really is a reproducable bug I made a test version of this scenario. Removed all red units and placed 3 tanks near this bridge shown in the screenshot.
That way I can quickly test tank movement near the canal. And it works just the same way. If a tank is ordered to drive on the right side of the canal, cross the road and then continue forward near the canal, it refuses to cross the road and drives down to canal and tries to drive below the bridge.
I tested this with 2 tanks and they both did it the same way.

The forum software does not allow me to attach the test scenario here, (1.74MB limit and the file is close to 3MB), but I can send the scenario for developers if they think it helps debugging.

 

 

Edited February 6, 2021 by SlowMotion

[chuckdyke]

it has to do with the tiles, I think. . Let scouts check the terrain, you can rarely trace a straight line if you do tile by tile. It is the reason you can't walk under the bridge too. It is near the bridge and that's where the problem is. Just my humble opinion. I try to walk under bridges in FB, SF2. Open the game in the editor and check the construction. 

[Sgt.Squarehead]

Looks to me like you told the tanks to drive through Heavy Forest Tiles, which they can't, so they tried to drive around them, getting you to where you are at.

I suspect the cause of this problem largely lies somewhere between the user-manual and the keyboard.  Statement retracted, due to wrongness.  Apologies. 

Edited February 6, 2021 by Sgt.Squarehead

[SlowMotion]

" Let scouts check the terrain"
If you mean infantry, they move from this place along straight line without any problems.

Tanks CAN drive from this area, it depends on how many way points you use. But especially if you try to tell them to say drive 100 meters straight ahead then the computer tries replace my plan with something it thinks is better - to go around some difficult to move area, I think, like Sgt.Squarehead suggested. And sometimes this means it tries to go around from left, driving to canal. Sometimes it goes around from right and avoids the canal.

When you are plotting movements between turns, the cursor shows if some tile cannot be moved through. Maybe it could show these "possible but difficult" tiles with some other cursor image as well? Like if there is Heavy forest. Now when I check my path by moving cursor slowly along the line it doesn't show any tile problems at all.

Edited February 6, 2021 by SlowMotion

[Sgt.Squarehead]

Just took a look at the map in the editor.....Turns out those are actually Light Forest Tiles, so the tanks could go through them.

Did you by any chance use just a single movement waypoint at the required destination and the 'Move' (or perhaps 'Quick') command?

I've come to think of the former as 'take the minimum effort route' (and the latter as 'do the same, but a bit quicker') as my troops always seem to do just that (they will often favour paths and moving over open ground rather than moving through cover). 

Thus when using the 'Move' command in cover I tend to favour a lot of short movement legs showing my pixelunits precisely where I want them to go.  This is absolutely critical in urban warfare scenarios.

PS - The map for this scenario is a beauty.....@George MC   Is this one of yours? 

Edited February 6, 2021 by Sgt.Squarehead

[chuckdyke]

20 minutes ago, SlowMotion said:

" Let scouts check the terrain"
If you mean infantry, they move from this place along straight line without any problems.

Tanks CAN drive from this area, it depends on how many way points you use. But especially if you try to tell them to say drive 100 meters straight ahead then the computer tries replace my plan with something it thinks is better - to go around some difficult to move area, I think, like Sgt.Squarehead suggested. And sometimes this means it tries to go around from left, driving to canal. Sometimes it goes around from right and avoids the canal.

When you are plotting movements between turns, the cursor shows if some tile cannot be moved through. Maybe it could show these "possible but difficult" tiles with some other cursor image as well? Like if there is Heavy forest. Now when I check my path by moving cursor slowly along the line it doesn't show any tile problems at all.

I can never move troops under a bridge even when I plot a waypoint under the bridge. During moving you see how the tiles light up. I encounter problems near bridges too, AFV's sometimes ignore bridges and get bogged in some little muddy stream. 

[SlowMotion]

1 hour ago, chuckdyke said:

I can never move troops under a bridge even when I plot a waypoint under the bridge. During moving you see how the tiles light up. I encounter problems near bridges too, AFV's sometimes ignore bridges and get bogged in some little muddy stream. 

While testing this bug I saw a tank drive under that small bridge. Not because I tried to do that, but because it just decided to drive in the canal. And many other strange things that normally rarely happen.

Edited February 6, 2021 by SlowMotion

[SlowMotion]

1 hour ago, Sgt.Squarehead said:

Just took a look at the map in the editor.....Turns out those are actually Light Forest Tiles, so the tanks could go through them.

Did you by any chance use just a single movement waypoint at the required destination and the 'Move' (or perhaps 'Quick') command?
 

I've come to think of the former as 'take the minumum effort route' (and the latter as 'do the same, but a bit quicker') as my troops always seem to do just that (they will often favour paths and moving over open ground rather than moving through cover). 

Thus when using the 'Move' command in cover I tend to favour a lot of short movement legs showing my pixelunits precisely where I want them to go.  This is absolutely critical in urban warfare scenarios.

PS - The map for this scenario is a beauty.....@George MC   Is this one of yours? 

While testing this I tried most movement commands: Move, Hunt, Quick and even Reverse which seemed to work better than just Move. Tried single waypoints and paths made from many commands. Short movements seemed to work better, but it was very unpredictable since very small changes in waypoints seemed to create very different driving. I think currently I'd suggest staying away from bridges and canals.

Yes, it's a good map and scenario. At least so far.

[Sgt.Squarehead]

It sounds like you've happened to find a particular bit of the map that the TacAI struggles with.....There's no clear or obvious reason for it to do what it does, its internal algorithms just calculate it that way, due to factors outside our sight.

I've encountered variants of this while testing on a few occasions, especially with AI controlled units.  In something I'm working on now, a platoon of IFVs always attempt to shortcut a kink in a road, across some dirt tites, but the ground is wet and they quite often bog!  In the end I gave up and assigned them all individual AI Groups so I could have maximum control of their moves.....We'll see how that goes in due course.

Edited February 6, 2021 by Sgt.Squarehead

[mjkerner]

The movement path is too close to the bridge. Bridges always pose problems for vehicles. Move that blue line out a couple of AS and there won’t be a problem, but within one or two AS of a bridge, vehicles usually will move erratically. Those light forest tiles probably aren’t helping anything, either.

[Combatintman]

The Tac AI also might be prioritising not getting shot over getting immobilised.  In which case the canal is the more logical choice.  As others have said, this is a case where micromanaging your move orders will probably help.

[George MC]

8 hours ago, Sgt.Squarehead said:

PS - The map for this scenario is a beauty.....@George MC   Is this one of yours? 

It is - thank you

it was redone for CMSF2. Old video from when I first released it. 

 

 

[Sgt.Squarehead]

1 hour ago, George MC said:

It is - thank you 

I'm starting to recognise your style (TBH I've emulated it here & there too). 

[chuckdyke]

10 hours ago, SlowMotion said:

While testing this bug I saw a tank drive under that small bridge. Not because I tried to do that, but because it just decided to drive in the canal. And many other strange things that normally rarely happen.

There is a similar bridge (but smaller) in FB and SF2 you see infantry walking through the stones or around the bridge but never actually using the concealment. I appreciate making maps is not as straight forward as we expect from the designer. 

[SlowMotion]

9 hours ago, chuckdyke said:

There is a similar bridge (but smaller) in FB and SF2 you see infantry walking through the stones or around the bridge but never actually using the concealment. I appreciate making maps is not as straight forward as we expect from the designer. 

In my opinion this movement behavior has to do with AI. How it chooses movement paths based on player's commands, map tiles, spotted enemy locations and such things.

Edited February 7, 2021 by SlowMotion

[chuckdyke]

Fair enough, naturally you try movements based on RL. Approach through a ditch which offers concealment. Reach the bridge place a waypoint under or directly on the other side of the bridge. What happens? They climb out of the ditch and cross in full view of the enemy. The moment I saw this scenario naturally I will convey may own experiences with bridges. 

Edited February 7, 2021 by chuckdyke
spelling

[Combatintman]

6 hours ago, chuckdyke said:

Fair enough, naturally you try movements based on RL. Approach through a ditch which offers concealment. Reach the bridge place a waypoint under or directly on the other side of the bridge. What happens? They climb out of the ditch and cross in full view of the enemy. The moment I saw this scenario naturally I will convey may own experiences with bridges. 

Don't bother over analysing it.  There is a perennial bridge bug which, despite persistent and continuing efforts to solve always seems to crop up no matter what fixes are applied.

[chuckdyke]

6 hours ago, Combatintman said:

Don't bother over analysing it.  There is a perennial bridge bug which, despite persistent and continuing efforts to solve always seems to crop up no matter what fixes are applied.

I agree with you, lets burn our bridges.