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Strange route choice

Fox

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Had allot of fun playing the Marsa el Brega mission the other day, however at one point I noticed my AI make a strange route choice (see below) and I am wondering what the cause was.

Chosen Route:
upload_2017-3-29_13-13-29.png

Control map:
upload_2017-3-29_13-12-22.png

The situation:
I had a panzer battalion that was moving in to secure the position it had successfully assaulted, as part of this the HQ (highlighted), AT and 88mm flak companies had to move in from their positions to link up with the tank companies. As can be seen in the image, Instead of taking the route I intended and heading pretty much straight east (as shown by the "avoidance" path measured from the HQ), the HQ and associated units decided to do a big loop around the salt marsh and come in from the rear.

The route type the HQ had selected for it's subordinates was "avoidance", however as can be seen by the control layer map the direct east route avoided the enemy far better than the loop around the salt marsh that was selected. The situation was only averted when I gave a new order (defend) on the same location.

Any ideas as to what could cause this behavior?
 
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Had allot of fun playing the Marsa el Brega mission the other day, however at one point I noticed my AI make a strange route choice (see below) and I am wondering what the cause was.

Chosen Route:
View attachment 5153

Control map:
View attachment 5152

The situation:
I had a panzer battalion that was moving in to secure the position it had successfully assaulted, as part of this the HQ (highlighted), AT and 88mm flak companies had to move in from their positions to link up with the tank companies. As can be seen in the image, Instead of taking the route I intended and heading pretty much straight east (as shown by the "avoidance" path measured from the HQ), the HQ and associated units decided to do a big loop around the salt marsh and come in from the rear.

The route type the HQ had selected for it's subordinates was "avoidance", however as can be seen by the control layer map the direct east route avoided the enemy far better than the loop around the salt marsh that was selected. The situation was only averted when I gave a new order (defend) on the same location.

Any ideas as to what could cause this behavior?

It's possible that the AI selected the safest route instead of the avoidance or shortest route.

The safest route avoids any enemy fire, the avoidance route minimizes the potential for triggering combat, and the shortest route is self explaining.

In addition routings also take into account the type of transport available to move the unit and the terrain that transport must traverse to reach the goal.

AT and 88-mm Flak companies are wheeled transport.

It's possible the terrain to be crossed could not accommodate using wheeled transport movement to complete the order as quickly as the largely road route selected.
 

Fox

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It's possible that the AI selected the safest route instead of the avoidance or shortest route.

The safest route avoids any enemy fire, the avoidance route minimizes the potential for triggering combat, and the shortest route is self explaining.

In addition routings also take into account the type of transport available to move the unit and the terrain that transport must traverse to reach the goal.

AT and 88-mm Flak companies are wheeled transport.

It's possible the terrain to be crossed could not accommodate using wheeled transport movement to complete the order as quickly as the largely road route selected.

I checked and both the AT & 88 flak had avoidance selected as their route type. I'm pretty certain there were no terrain problems, both routes are mostly flat desert ("clear" terrain type), the route around the salt marsh only has a little bit of road at the end. Ultimately I'm not sure of any reason that any of the path finding methods could lead the AI to pick the route that it did, as it is longer, slower and goes through terrain that is much more heavily controlled by the enemy.
 
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Daz

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Sometimes the AI does some crazy *%&!#*!
Would be interesting to see if it changed the route again if you had left it alone, as sometimes it does do a reassessment and decide on a better route.

The best solution I can give you, is to monitor your subordinates and dish out advice and disciplinary action as necessary (delete the old order and give them a more specific orders for a better route).
The defend in situ tick box, in the attack order dialogue, is very useful to help with this after an attack, if there is any likelihood of the HQ and support taking a scenic route.
Experience will help you to determine when this is necessary.

From my experience, I would advise that if there is no obvious road from the FUP to the assault waypoint, tick the defend in situ box. After the attack, during the reorg stage, drag select the line units that are on the objective and give them a defend in situ order. Then give the HQ with its attached support units a more specific move order, (probably using shortest path is best over rough terrain to move though the line units cleared assault route) to re-join them.
 

Fox

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Yeah I fixed it by issuing a defend order on the same objective and they followed the intended path, I'm just surprised the avoidance algorithm chose that route considering the control layer (which I'm assuming the AI pathfinder uses in some way to help find its route) showed that route as being blocked by the enemy.
 

Daz

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There is still a bug in the code, where a formation with an attack order, after a long drawn out fight, will report (via the message log) that the attack has stalled.
Instead of bunkering down like it is supposed too, the AI turns the assault into a move to the attack waypoint in road column and probably (not confirmed) quickest route.
Is it possible that is what has happened in this situation?
If it is, please send a save to Dave, as it would be nice to get this fixed once and for all.
 

Fox

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I don't think that was the problem in this situation, the assault on its objective was successful and the battalion had started securing the objective at 20:46 (32 mins before the screenshots) from the logs, and chose to take the avoidance route (which is sensible). I think it must have been a problem with path-finding algorithm, as both the PATH tool and the AI units thought the best avoidance route was to go up north around the salt marsh, despite a look at the control layer confirming this not being the case.

That reminds me though I did encounter another serious issue on this mission. My first attempt to rectify the route problem was not to issue a defend order (I only did this later) but first I changed the route type specification for the Battalion HQ's attack order from "unspecified" to "Quickest" (as the quickest route was definitely not around the salt marsh). This caused a severe performance slowdown (1 minute game time increments were taking ~10 seconds to process at >> speed, this normally runs at 1 minute/second for me ) until I issued the new defend order. I have a save that reproduces the problem.
 
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I don't think that was the problem in this situation, the assault on its objective was successful and the battalion had started securing the objective at 20:46 (32 mins before the screenshots) from the logs, and chose to take the avoidance route (which is sensible). I think it must have been a problem with path-finding algorithm, as both the PATH tool and the AI units thought the best avoidance route was to go up north around the salt marsh, despite a look at the control layer confirming this not being the case.

That reminds me though I did encounter another serious issue on this mission. My first attempt to rectify the route problem was not to issue a defend order (I only did this later) but first I changed the route type specification for the Battalion HQ's attack order from "unspecified" to "Quickest" (as the quickest route was definitely not around the salt marsh). This caused a severe performance slowdown (1 minute game time increments were taking ~10 seconds to process at >> speed, this normally runs at 1 minute/second for me ) until I issued the new defend order. I have a save that reproduces the problem.
Were the enemy units the HQ and attached units encountered visible at either current or recent intelligence visibility settings?

A game save, (ideally before the move started), would supplement the marked up image to shed more light on the circumstances the AI faced when making the route selection.
 

Fox

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This image is from the closest save I have, the time is 16:41; this is 4 hours 37 minutes before the previous images, and 4 hours 5 minutes before the HQ started securing the object (at 20:46). Intel filter is set to recent.

upload_2017-3-31_21-22-20.png

This is image from the same time as previous posts (21:18) but with the intel filter set to recent.

upload_2017-3-31_21-21-13.png

As can be seen the enemy position north of the salt marsh was clearly visible in the daytime (they were visible there the whole day), when night fell line of sight was lost but the area in question is still marked as hostile on the control layer.
 
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This image is from the closest save I have, the time is 16:41; this is 4 hours 37 minutes before the previous images, and 4 hours 5 minutes before the HQ started securing the object (at 20:46). Intel filter is set to recent.

View attachment 5159

This is image from the same time as previous posts (21:18) but with the intel filter set to recent.

View attachment 5158

As can be seen the enemy position north of the salt marsh was clearly visible in the daytime (they were visible there the whole day), when night fell line of sight was lost but the area in question is still marked as hostile on the control layer.
The save is necessary.

A developer needs to look at what background information was evaluated in the AI algorithm used to define the selected the path before your question can be answered.
 

Kurt

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I have the saves, but how to upload...
compress into a zip folder using something like 7-zip , right click on the file and it should give the option to " compress to zip folder ".
 

Fox

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Lol I didn't see the upload a file button that was right in-front of me.

1st save (16:41) is from before the incident, 2nd a bit after it started occurring and the 3rd after I changed the route type. It was the 3rd save that was having the very slow performance for me.
 

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simovitch

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Just having a quick glance at your saves it looks like the AI evaluated the enemy anti-armor/inf threats, not so much the enemy controlled areas which isn't too far off the mark. From experience I rarely have a satisfactory result using "unspecified" in the combat zone.

The slow down from choosing quickest is odd, and may be related to the size of the map and all those salt marshes. Hopefully Dave will have a look soon.
 
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Lol I didn't see the upload a file button that was right in-front of me.

1st save (16:41) is from before the incident, 2nd a bit after it started occurring and the 3rd after I changed the route type. It was the 3rd save that was having the very slow performance for me.
Loading the second save, I note that the order issued was to attack (rather than move) using the fastest speed and an unspecified route. The units you wanted your headquarters to link up with were already in the attack zone in either a resting status or halted and deployed with no enemy units located in that zone. During the HQ's move to the attack zone, only two enemy units on the northeast side of the map became visible to the moving force according to both the recent and current settings for intel. Those sightings occurred well into the execution of the move.

The facing selected for the attack was left to the AI, and was toward the southwest where the bulk of the enemy units were spotted by friendly forces. A direct move to the attack zone would have taken the HQ unit through currently known anti-personnel / anti-armor fire enemy zone while the selected route went around that zone and used both flat terrain and both a secondary and primary road route through the salt marsh outside of the enemy fire zone to move the combined track wheeled force quickly to the force link-up in the attack zone.

I think to get the route you wanted, you had to order your forces in the attack zone to hold in place (or defend), dismiss the attack order issued to the headquarters unit, and then issue a new order to move to the HQ and the remaining forces. When you issue an order on top of the attack (e.g. issue a move order without cancelling the original the attack order) I believe the force will try to complete the first order before implementing the second.

Running from your first save, I get a different result from the attack order, with the HQ and all units taking a more direct route to the attack zone. I believe this is because the enemy moved a unit to the west of the salt marsh terrain blocking the roundabout route taken by the HQ unit in your save.

I note, using the recent intel setting, that most of the units you show on your illustration to the northeast side of the map abandoned the anti-tank obstacle and moved to the combat zone behind the obstacle along the main route.

Bottom line is the HQ you wanted to move using the fastest speed to link up with your attacking forces selected a route that was devoid of any current or recent enemy sightings and thus avoided known fire control zones rather than using a direct route through a known enemy fire control zone.
 
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