Tuesday, March 13, 2012

Combat Mission Battles for Normandy Commonwealth Forces - Watch Out! The AI Got Smarter

It's a test I've run since the original Combat Mission Shock Force hoping that the computer controlled units would use cover and/or concealed routes of advance. After a while I gave up: the computer controlled units couldn't see neither the tree nor the forest.

After a certain discussion in a community forum elsewhere I decided to retest this with the Commonwealth Forces module and the results were shocking good.

First a disclaimer: none of these "tests" are intended to be comprehensive, conclusive, scientific or reflecting a  tactically credible situation. They are intended to see what the computer-controlled bots do in a particular situation. In that spirit, we move into contact.

The test is simple: a computer controlled enemy force has to advance towards the other extreme of the map under the "advance" order with the "normal" modifier for fire and movement. The computer controlled side's objective is as wide as the map itself. The tactical challenge for the AI bots is to survive against a bunch of machine guns in a trench near the objective. The AI has two choices: a frontal attack through open terrain or using a patch of trees that offer some cover and concealment.

So for comparison, let's take a look of how it works in Combat Mission Afghanistan (I've lost my copy of Combat Mission Shock Force, the Marines and the British module to Battlefront's DRM so I can't compare with those right now but I remember the results not being too different).

Afghan mujahideens (blue) have to move to the other extreme of the map.
Right after the scenario starts, the computer-controlled mujahideen completely ignore the trees and go straight into the open terrain. The casualties pile up quickly.
Now a similar setup but with Combat Mission Battles for Normandy Commonwealth Forces.

German soldiers (grey icons) have to move to other extreme of the map. 
And ... Wait for it ...

... The computer controlled Germans choose the woods! 
Yes fellows, the AI bots made a sensible choice and approached the trench using an avenue of approach that offers some cover and concealment. Very good news.

By mid-game, the Germans are ready to continue their advance towards the other extreme of the map. They have avoided the open terrain in the left.

What's the trick Battlefront pulled for this I don't know. What I suspect is that the AI bots were looking for the terrain tiles in the base of the trees (they are named something like "light woods" IIRC).

The computer controlled Germans in the wooded terrain at the right flank. The open terrain they wisely avoided is visible in the background. Those terrain tiles under their bellies may be useful for something else than good looks.
My guess is based on what happens when you change the terrain tiles underneath the trees to "grass" (see below).

When the terrain tiles underneath the trees are just grass (not "light woods") the computer controlled Germans just ignore the trees and go straight into the open terrain. The butchery rages on.
I hope this is useful for scenario designers.



M.Dorosh said...

Interesting observation; if true the downside is in the modelling of "orchard" terrain - by definition a row of trees devoid of underbrush (i.e. nothing in the terrain tiles underneath). Given that Normandy was crawling with orchards, this will mean a conscious effort on the part of scenario designers to work around your observation, or at the least, confirm them.

JC said...


Thanks for your comment.
A terrain tile with grass will be ignored by the computer controlled units, no matter what the tree cover is. At least is what it seems. The AI appears to ignore blocked LOSs as cover.