Arma 2 and it's stand-alone expansion Arma 2: Operation Arrowhead package.

  • Lifelike combat simulation
  • Story driven single player
  • Resource management
  • RPG elements
  • Unique AI combat system

Built upon over 10 years’ experience, Arma 2 thrusts gamers into the heart of the most realistic military combat simulation ever developed, featuring cutting edge technology, vast, detailed environments and authentically modelled units, weapons and vehicles. Branching, player-driven campaigns offer both solo and cooperative gameplay, accompanied by a huge range of single and multiplayer modes.

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Blog RSS Feed Report abuse Latest News: The challenge and saga of Zombie Pathfinding

About DayZ with 6 comments by TheUnbeholden on Aug 20th, 2014

This devblog will be focused on describing the progress with one of our biggest issues: Zombie Pathfinding.

Development Priorities and Pace

Our major focus has been on establishing the architecture, both in the team and in the game, in order to deliver best in the future. This involved us drastically increasing the size of the team working on the game. This had a severe short-term impact on our progress as our existing team had to devote time and resources to training and planning. The new zombie pathfinding is a good example of this approach beginning to produce results.

Some examples of future major changes coming as a result of this new focus:

  • Entirely new rendering system (allowing potential upgrades to DX10 or DX11, ports as well).
  • True multithreading / multicore for servers and possibly clients.
  • Completely new animal AI that mirrors an actual animals behaviors.
  • Redeveloped “action” system, replacing the mouse-wheel scroll action system.
  • Complete refactoring of the inventory system. While not a big change for users, possibly allows some more advanced systems to be implemented and better performance and less bugs.


Zombies have proven to be one of the most difficult to develop components of the game. When we were developing the game we realized that in the time we had, we would need to work within the parameters of the AI already in the engine. In the engine, AI is calculated on a “per agent” basis, with some caching for things like targets (shared target info, etc…). In the mod, this was dropped in favor of calculating visibility and target info on a “per player” approach. This meant that zombies in the mod were simply pawns, activated by players moving around.

In addition to behavior problems we also experienced problems with pathfinding and collision for the AI. We were getting the engine to do things that it was never designed to do, especially regarding interiors of buildings. We attempted to refactor these solutions to accommodate our changes but, as can be seen by playing the current build, they fell short of our expectations. In the end we decided it would be easier to develop a new approach from scratch.

The Challenge

There are many exciting solutions available for pathfinding, it’s fairly standard fare in the video gaming industry. Our problem was not unique, but our situation was: our world is very big yet it requires the same precision as a small one.

The team devoted to solving this decided to use navigation meshes. The serious problem it presented, though, was how to generate these meshes, with nearly 2 million objects on the map doing it by hand would not be an option. So a method was devised to split the world up into grids, and then raycast at a precise interval and generate chunks of navmesh. This is all done during the packing process and “baked” out into data that can be read by the server and client. This uses the wonderful approaches outlined in the open source navmesh project Recast and Detour.

The Results

I spoke to Martin Slavkov, programmer behind the solution, to help me outline the result with some screenshots.

Generating the Navmesh (view Imgur Gallery of generation)


A small program was developed to read through the world, load all the objects, and then work its way through tracing billions of lines to calculate the ability to move. This then works out not only where outside you can walk, but inside as well. It gives great precision while still working for a very large scale world both indoor and outdoor. Having a unified solution for pathfinding makes implementation much easier.

Use in-game (view Imgur Gallery of navmesh in action)

The engine is then able to load the chunks in as it needs. It does use some memory (around 600mb extra, maximum), but it only loads the chunks it needs. However as we are moving to 64-bit on the server side, this reduces any potential issues with memory.


Performance optimizations can be very significant. Currently the team are working on parallelizing the AI pathfinding function so it can operate on a separate core. With all new functionality we are developing in this way, unfortunately that means that it can take longer for us to develop but the results for performance can be massive.

Previously two different systems were used for navigating AI. The exterior one handled navigation around static and dynamic objects, and an internal “path” system was used for building interiors. This involved artists defining paths that AI could follow. We had to drop this interior method because of the massive performance issues with large numbers of agents.


In the screenshot above, you can see a path between two red points. Because the system is now unified it means that more efficient (and more natural) pathfinding solutions are available to the AI, at a fraction of the performance cost as before.

Report from the Lead Artist, Chris Torchia (View Imgur Gallery of new art)

I’m happy to report on the loads of content which will soon hit experimental servers. Recently the Prague and Bratislava studios had our first meet and greet so I was able to get a first hand look at all of the ongoing work by the artists and animators on our new animals. We have a basic implementation of prototype animals that will be swapped out by our Bratislava artist’s work which is looking incredible!

Improvised fishing tackle and a carp were created, which players will be able to catch in ponds. We have also created some filet models which you will eventually be able to cook. This will all add up to be a literal game-changer. Speaking of animals - we also met Big - the office pet tortoise in Bratislava. Hm, that gives me an idea…

Our character artist is further expanding with the addition of a new large-capacity police vest to go along with our ?MON-inspired ???? uniform. We have also started working on EMT, Firefighter, and finalizing the Gorka uniforms.

Fireplaces, Hunting, And being a lumberjack!

We pulled fireplaces and hunting from the previous update in their state at the time, we felt they would hinder gameplay not enhance it. The extra time has been spent improving gameplay aspects and also identifying how we can better support it.

The build to experimental will show the basic structure of how this will work. Chopping wood from trees now gives logs, and after a certain time, the trees will be “expended” and fall over. Tree cutting is done by holding an axe in your hands, and using the mouse-wheel action menu. This is a prime example of why we want to remove the mouse-wheel action system. Instead of this, we envision you simply hitting the tree with the axe and being rewarded with wood - but that is for the future.

Fireplaces can be upgraded with stones, which are recovered from the ground around rocky areas or by hitting rocks with a pick-axe. Fireplaces can be crafted by making a “fireplace kit” out of items such as rags and kindling. Kindling is recovered by searching the forest floor for sticks. All these scavenging aspects need more refinement as part of a new action system, but they’re exciting changes that will pave the way for more complex systems such as horticulture.

Bratislava Team Visit (view Imgur Gallery of the visit)

We visited our team in Bratislava -  they have a TURTLE!

The next update

Our current targets have us putting out builds to stable once a month, a huge inspiration for approach we aspire to is Prison Architect who do this very well. We have no set timeframe for experimental releases, these are done to assist us with preparing for stable releases.

Above all else, it’s vital that people appreciate several things:

  • Different tasks take different amounts of time
  • Priorities for tasks are built around what is needed based on dependencies, not what is most needed to satisfy the game design
  • Scheduled builds are targets, not absolutes. We will delay and postpone builds where we are not confident in their status.
  • Devblogs are no longer scheduled weekly, and are done as often as we can to provide background for our progress.

The Final Word

This is an extremely exciting time for us all as we come out of two months of very aggressive growth. We’ve expanded the team a great deal, taking a huge risk in doing so. That risk is paying off, and we’re excited to see the massive impact that the pathfinding and collision changes will have on the DayZ experience.

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ARMA 2: Combined Operations


Oct 17, 2014 Mod Armée Française Civil Extension Full Version 0 comments

Set up under the project MAFXExt, this mod is a continuation of MAF2Ext. It aims to provide equipment and units of the French army is not present in the...

DAFmod v0.91 Released! part2
ARMA 2: Combined Operations

DAFmod v0.91 Released! part2

Oct 5, 2014 Dutch Armed Forces Full Version 1 comment

The latest version of the Dutch Armed Forces module for ArmA2: CO has been released today (05-10-2014). Many fixes, upgrades, additional units and some...

DAFmod v0.91 Released! part1
ARMA 2: Combined Operations

DAFmod v0.91 Released! part1

Oct 5, 2014 Dutch Armed Forces Full Version 0 comments

The latest version of the Dutch Armed Forces module for ArmA2: CO has been released today (05-10-2014). Many fixes, upgrades, additional units and some...

Wallpapers 1
ARMA 2: Combined Operations

Wallpapers 1

Jul 31, 2014 Indochine 1946 - 1954 Wallpapers 1 comment

This is the first Wallpapers. A Douglas dc 3 on Dien Bien Phu landing.

DAFmod v0.9001 Released! part1
ARMA 2: Combined Operations

DAFmod v0.9001 Released! part1

Jul 21, 2014 Dutch Armed Forces Full Version 1 comment

The latest version of the Dutch Armed Forces module for ArmA2: CO. The package has been split in two parts to make it compatible with ModDB. The latest...

DAFmod v0.9001 Released! part2
ARMA 2: Combined Operations

DAFmod v0.9001 Released! part2

Jul 21, 2014 Dutch Armed Forces Full Version 0 comments

The latest version of the Dutch Armed Forces module for ArmA2: CO. The package has been split in two parts to make it compatible with ModDB. The latest...

Post comment Comments  (0 - 10 of 20)
majorkyle May 13 2014, 6:38am says:

Guys please see that blog hope you like this new idea and please forgive me if i did something wrong because this is my first blog.

+2 votes     reply to comment
TonyCruz Jan 3 2014, 1:22am says:

Where do we download the games and mods? Please help, It could be right in front of my face but..yeah...please someone help

+3 votes     reply to comment
AubeSangante Feb 15 2014, 12:27am replied:

Buy it then...It's not he free game.

+3 votes     reply to comment
Jastrząb Feb 7 2014, 9:07am replied:

For Arma mostly froam here.
and the games?? I have no idea what are you asking exactly.

+4 votes     reply to comment
SaxyChad Jul 1 2013, 6:56pm says:

If your game says bad serial number, Exit out of all steam windows, right click and run as administrator. Then go into your steam games and uninstall both ARMA II And ARMA II OPERATION ARROWHEAD. Then install ONE AT A TIME. This should work and our game should now run smooth.

+3 votes     reply to comment
Maksman Feb 1 2013, 10:18pm says:

can you get dayz with this?

0 votes     reply to comment
MrBlorx Jul 15 2013, 2:09pm replied:

Yes. Arma 2: Combined Operations is preferred if you're going to play Dayz.

+3 votes     reply to comment
greenland99 Jan 8 2013, 3:38am says:

what mean bad serial number??

0 votes     reply to comment
LaGNeVeRFaiLs Aug 10 2013, 11:31am replied:

Bad or Wrong Serial Number or Incorrect Serial or the Serail number is not meant for the Copy of the game

+2 votes     reply to comment
ceeking Nov 19 2012, 4:17am says:

oh sorry i meant this comment for normal arma 2 the free version

-2 votes     reply to comment
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ARMA 2: Combined Operations
Developer & Publisher
Bohemia Interactive
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Release Date
Released Jun 26, 2009
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Highest Rated (2 agree) 10/10

Truly an amazing instalment when both games are put together, a must have for FPS and Simulation game lovers.

May 4 2011, 10:55am by TankGun

Tactical Shooter
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RT @Arma3official: Every Vote Counts! To support Capt Miller's campaign, you can join his competition and win a true #Arma3 fan package! ht…

Oct 24 2014, 7:12am by bohemiainteract

Arma 3 has free weekend @steam_games right now, it's best time to test it before using that 50% discount @Arma3official #arma3 #free #games

Oct 23 2014, 1:28pm by foltynd

RT @Arma3official: SITREP #00079! FROM: Project Lead / TO: #Arma3 Users / PRECEDENCE: Flash

Oct 21 2014, 2:42pm by foltynd

RT @Gekonn: Can you guess what feature is making its way to #Arma3 Launcher? #workinprogress #soon(tm)

Oct 20 2014, 9:51am by foltynd


Aug 14 2009, 9:33am by arma2pc

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