2013-04-15 Getting better at generating missions, CWR2 beta units and Project 82 Pucara units Zoom

"Cannot find maneuver space to execute a coordinated attack...". If PlannedAssault fails to generate a mission, it most frequently is for this "lack of maneuver space" reason. In case of eight 4-tank platoons being asked to attack through a single valley in Takistan, it's hard to blame the mission planner. However, in some other cases, the planner wasn't seeing all the options available.

Form-up position candidates for unit Hotel

Checking form-up positions for crossing routes

CWR2's M2A2 Bradley in combat (Arma2)

I've just updated the planner behind PlannedAssault with a new set of algorithms to identify and select the most promising form-up positions and avenues of attack. The new approach takes into account more candidate form-up positions which also have higher quality. It balances multiple prongs in a joint attack better. This improvement applies to all supported games and simulators, from Arma1 to Arma3, Iron Front and any VBS.

And, most important, it is better at finding maneuver space. It is successful more often based on off-line runs against 100s of your missions.


In the first two images above, you'll get a glimpse of the new approach. The image on the left shows potential form-up positions for combat unit Hotel and its transport (not shown), along with course avenues-of-approach to the objective. The image in the center illustrates a sanity check performed when picking form-up positions for multiple units; when a combination of form-up positions leads to units crossing each other towards the form-up, this combination is rejected.

Column of CWR2's new T-64s and BRMD-2s (Arma2)

A CWR2 OH-58/AH-64 hunter killer team (Arma2)

CWR2 SAS engaging P82 Pucara with Stinger (Arma2)

This update also brings a few new (Cold War era) units to the unit database. Ready for inclusion in your mission are new additions to the Cold War Rearmed 2 (CWR2) add-on: the M2A2 Bradley IFV, the OH-58 Kiowa scout helicopter, and Warsaw Pact T-64 tanks and the BRDM-2 family of recon/HQ vehicles.


Also new is the Argentine FMA IA-58A Pucara by Foxtrot, which combines nicely with the CWR2 UK forces.





2013-02-14 Better defense: spread out more, concealed better, and covering the avenues of approach (Arma2OA/CO, IronFront) Zoom

The past couple of weeks have been spent improving the AI's defense in PlannedAssault's missions, and now the results are hard to spot!


As the first screen shot makes clear (can you spot the two concealed and spread out M1036 TOW HMMWVs?), attacking a position becomes a lot more interesting when it is properly defended. With PlannedAssault-generated missions now offering stronger defense for Arma2OA/CO and Iron Front missions, I'd like to explain the changes.

Two TOW vehicles spread out amidst trees and buildings (Arma2)

Planner input: the position to defend

Planner analysis: likely threat avenues of approach

The improvements in defense mainly come from a combination of terrain and threat analysis (as performed during mission planning, by PlannedAssault) and better position selection (as performed by a new script during as part of the mission itself), as follows:

  1. In the mission planner, the position to defend, and the likely position of hostile forces are analyzed.
  2. In the mission planner, the defensive position is partitioned in 'pizza slice' sectors. Potential threat avenues of approaches are generated, and analyzed for traversing a defensive sector's front or area.
  3. Finally, the mission planner selects the key sectors to defend based on expected threat movement. The defending forces are assigned to those sectors in a way that best matches the expected threat type for the sector. Sectors likely to be used by hostile (armored) vehicles are preferably defended by tanks or units with an 'heavy AT' capability. Sectors likely to be used by hostile infantry are preferably defended by IFVs and infantry.

Planner analysis: chosen sectors and allocated forces

Generated mission: sectors and threat avenue of approach

In game: candidate vehicle positions in Keiler's sector

  1. During the generated mission, the defenders each are ordered to move into their sectors. For each sector, the mission planner has included in the mission a list of positions representing the likely threat avenues of approach (see the black dots in image #4). Once the defending unit arrives in his sector, he will use this list of positions to pick the most suited defensive positions.
  2. As soon as the defending unit arrives in sector, a newly developed script is triggered. This script first generates number of candidate positions inside the sector that are suited to hosting the unit's vehicles/men: empty positions for vehicles near houses/trees, and bush / forest edge positions for infantry.
  3. This script then tests each of the candidate position for having lines-of-fire onto the threat avenue of approach positions, and for being placed central and deep in the sector. The most suited candidate position then is selected, neighboring positions are culled, and the next best position is selected for the next vehicle. Rinse and repeat. This yields nicely spread out positions in the sector.

In game: chosen vehicle positions from the candidates: spread out...

In game: the result, one of the Keiler group vehicles positioned

In game: the result (continued): another vehicle from Keiler's group

  1. This script finally sends each vehicle to its individual battle position and orders it to orient itself towards the threat avenue of approach. Image #7 shows the result: a hard to spot Bundeswehr Jaguar tank destroyer positioned near and in front of houses. He has a good view at the road where hostile forces are expected, while at these hostile forces will have troubles spotting him. (The pink floating ghost HMMWV is a debugging marker I use to be able to easily spot assigned vehicle positions - you won't see it in generated missions).
  2. Image #8 shows a second vehicle from the same Jaguar tank destroyer platoon being positioned 50m east wards, covering the second incoming road in the platoon's sector. (Again, the pink floating HMMWV is a debugging marker to facilitate spotting the Jaguar, and isn't shown in generated missions).

AAVP platoon spreading out to cover two access roads (A2CO)

Better positioned defenders: the attacker's perspective... (A2CO)

Dangerous crossing: road sections covered by Milan gunner (A2CO)

Once positioned, a defending group will remain in position until (a) triggered to fall back to a 'GUARDED_BY' trigger position or (b) engaged by an enemy. It retains its traditional dynamic (GUARD) defensive behavior.

With these changes, defenders will occupy better positions offering more visibility and lines-of-fire into potential threat avenue of approaches, while occupying less conspicuous positions and spreading out vehicles better. Also, static vehicles with anti-tank capabilities will keep their crew fighting for longer after being hit.


Please remember, this is still Arma2's AI, which means some things cannot be controlled from my new defensive positioning script. In particular, armored vehicles cannot be told to face a specific direction with their hull and turret, and they risk being recalled into 'formation' if the group's lead vehicle is late moving into position...


However, the script is effective most of the time, an improvement over the vanilla defensive behavior, and a gap filler until the time Arma's AI receives an understanding of battle positions like Steel Beasts does.


Key ingredients in the defensive positioning script are the selectBestPlaces, findEmptyPosition, lineIntersects and terrainIntersect(ASL) commands. They are the reason this improvement is implemented for Arma2:OA, Arma2:CO and IronFront but not for Arma, JCOVE, and VBS2 1.x.

I should be able to make this work for VBS2 2.0 as soon as BI Simulations releases the VBS2 2.0 upgrade for my PE license.



2012-07-07 Bridge crossings obscured by smoke screens, immediate insight in the generated plan, and Operation Frenchpoint units Zoom

In today's update, I am providing something extra for attackers having to cross a bridge in their advance: artillery delivered smoke screens. These smoke screens obscure the attacker's moves across the bridge. The smoke screens make a successful attack more likely even with the defender explicitly defending bridges (as of the previous update).

If the attacking team has an artillery unit able fire smoke or WP, this unit is ordered to fire an obscuring smoke screen to ease crossing a bridge under fire. Smoke screens are being fired after the preparatory artillery strikes on the objective, if any.

Artillery delivered smoke screen starting (Arma2)

Artillery delivered smoke screen fully built (Arma2)

US Marine advancing across smoke obscured bridge (Arma2)

The (AI) artillery unit will fire a smoke curtain on the far side of the bridge, by firing smoke or WP shells perpendicular to the bridge and some 20 to 80m apart (depending on the wind direction). This is done repeatedly, since smoke shells provide smoke for less than a minute and the smoke cloud takes time to build. The smoke screen is maintained for a period of about 8 minutes. The smoke screen will be 50 to 300m wide, depending on the number of guns and the wind direction. (Smoke screen calculations are based on WWII British Artillery Corps documents).

For now, PlannedAssault will solely generate smoke screens orders for missions involving bridge attacks and targeting Arma2 (base, OA, CO); effectively this means missions with attacks across bridges on the Zernovo and Faysh-Khabur maps.

French Tigre with HAD load-out near smoke covered bridge (Arma2)

The generated plan provided as feedback (Arma2)

French AMX10 R-CR on far side of obscured bridge (Arma2)

This update brings another improvement: immediate insight in the generated plan for the player's side, on the 'generated mission' screen. There, the same information is given that would otherwise first be seen as part of the in-game mission briefing. The generated plan doesn't go in much detail, but indicates the transport assignment and how fire support is being employed (whether artillery is within range to provide the necessary support).

One of the screen shots in this update provides a nice example of such a generated plan. Having the plan information available should help quicker round-trips while tweaking a mission.

French AMX10 R-CR and VBCI stuck on bridge (Arma2)

A platoon of CAESAR mobile guns deployed on line (Arma2)

OFrP's Close-up of the control system for the CAESAR gun (Arma2)

For the A2:OA and A2:CO games, I've replaced the Hexagon add-on entries by the corresponding Operation Frenchpoint (OFrP) add-on units. Operation Frenchpoint is the successor add-on for Hexagon, adds A2:OA features, and includes all the Hexagon units and a bunch of additional units. Especially impressive are the CAESAR mobile guns (which aren't available for selection in PlannedAssault until the Operation Frenchpoint add-on team provides ballistics for the CAESAR's ammo).


Finally, I've included a script in generated Arma2 missions that configures tank crew to remain in their tanks if these get immobilized. This behavior is available from Arma2 1.60 onwards, and results in an innocent error message if you haven't upgraded to that version.


Have fun!



2012-05-27 Bridges over troubled waters Zoom

Bridges and rivers often lead to interesting battles. Also in Arma2. Recently, two new Arma2OA maps were released that featured bridges which the Arma2 AI is capable of crossing most of the time*.

To benefit from this, PlannedAssault now recognizes bridges and includes nearby bridges in its defensive plan.

One of Zernovo's five bridges (Arma2)

An M1 Abrams platoon crossing the bridge under fire (Arma2)

AI and players are given explicit instructions to defend a bridge (Arma2)

With Jakerod's Zernovo map and =KCT=Blackmamba's Faysh Khabur map, we have been given two beautiful maps that happen to work for the Arma2 AI. Zernovo is a small map designed around a real-life German river section. That rivers is crossed by multiple bridges so they connect several small towns. The map features West-European farm lands with subtle height differences separated by tree lines. Roads are slightly elevated, enabling hull down positions.


Faysh Khabur represents the Iraq-Syria-Turkey border area in Iraq's Dahuk province. The area is partitioned by a wide yet shallow Tigris river, with just two bridges allowing traffic to cross. The terrain is barren, offering little concealment and long engagement ranges.


What these two maps have in common is that their bridges present great tactical opportunities, especially for the defender. Unless the attacker is capable of amphibious assaults, the bridges funnel him into predictable approaches, as you can see from the screen shots in this update.

A pair of Stryker MGSs blocking the bridge (Arma2)

Faysh Khabur's northern most bridge (Arma2)

Modern Russian infantry ready to the stop the enemy advance (Arma2)

To make the defender benefit from bridges, I've extended PlannedAssault with the ability to (1) identify bridges and causeways in Arma/VBS2 terrain, (2) include nearby bridges in the selection of defensive sectors, (3) explicit generation of 'defend bridge' orders for AI and player teams, and (4) pre-registered artillery targets at the far side of bridges included in the defense.


To identify bridges I've had to perform some new terrain analysis. The Arma/VBS2 terrain files do not indicate which objects are bridges, the default location types don't include bridges, and the in-game scripting API does not support queries for bridge objects.

It isn't too hard to identify bridges: typically they are roads with water on both sides. It proved harder to get rid of the false positives: roads with water on both sides that aren't bridges, such as piers and harbor installations and land ends.

All maps featuring bridges (Zernovo, Faysh Khabur, SaraLite) and causeways (Quesh-Kibrul) have been updated with a new terrain database identifying bridges for mission planning.

New: bridges are included in the defensive plan

Amphibious vehicles don't need bridges to cross rivers (Arma2)

The 'defend bridge' order and corresponding sector (Arma2)

To identify the most important defensive sectors for an objective, I generate set of sectors around the objective and test which of those sectors are likely to be used by an enemy trying to attack, with infantry or with vehicles. I've updated this approach by adding nearby bridge sectors and giving these bridge sectors a bonus for predicted enemy attacks across them. This bonus reflects bridges being effective bottlenecks that are more easily defended than a wide sector.


One of the pictures in this update shows the difference between defensive sectors as selected previously versus defensive sectors selected while taking into account bridges.


When bridge sectors are included in the defense, the teams are given explicit orders to defend the bridge, per the usual tasks generated with each and every PlannedAssault mission. These are shown in the briefing, and in the HUD as 'new task assigned'.

Artillery fire into the pre-registered far side of the bridge (Arma2)

Spetsnaz GRU patrol in Mtn Flora/Sumrak camo (Arma2)

Modern Russian infantry manning a D-30 gun (Arma2)

The final bridge related improvement is a continuation of the earlier defensive behavior. At the far end of each of the defensive sectors a pre-planned fire support target ('TRP') is defined, into which fire support is requested by the AI when hostile ground forces are observed there. This means that the far side of the bridge is 'prepared' for a quick artillery mission. When the attacker moves into this area and, typically, bunches up to get across the bridge, this pre-planned fire support may take a lot of punch out of his attack.


Something not related to bridges: I've been testing my generated missions for Zernovo and Faysh Khabur using two new Russian Federation add-ons. First is Colonel Stagler's Spetsnaz GRU in various kinds of uniforms and camouflage, with and without backpacks. Second is Cmp's Russian modern moterized infantry, in flora, digital woodland and desert camo. Both have been added to the add-on database for Arma2:CO.


Enjoy the bridges!




*: Although many more (Arma1, VBS2 and Arma2) maps feature bridges, on very few of those maps the AI is able to reliably cross these bridges.