An epic bug hunt featuring a unique blend of co-op play and squad-level tactics. With your friends, form a squad of four distinct IAF Marine classes. Plan your attack using an unlockable arsenal of weapons with countless loadout configurations against a wide variety of aliens.

Blaze your way through an overrun, off-world colony, eradicating the alien infestation in environments ranging from the icy planet's surface, to a subterranean lava-flooded mining facility.

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Blog RSS Feed Report abuse Latest News: The making of a node graph

About Swarm Director 2 with 2 comments by BenLubar on Jul 7th, 2014

If you play an Alien Swarm map, you see something like this:

In-game view of Area 9800 Landing Zone

If you're a mapper, you see something like this:

However, if you're an alien or a marine bot, you see something like this:

Node graph from Area 9800 Landing Zone

Today, I'll explain the third view. The one you don't see unless you're actually part of the game. The little yellow boxes (nodes) tell the AI "you can go here". The game automatically connects nearby nodes to form a node graph. It's like a street map, but there are no houses and streets can appear and disappear at any time if something blocks a path between nodes.

Hammer view of Area 9800 Landing Zone without propsHammer view of Area 9800 Landing Zone with props

On the left is a room with the props removed. On the right is the same picture, but with the props. Open them in tabs and flip back and forth a few times if you can't connect them in your head.

There are two main problems with this layout: there are no hints for marine bots and some of the nodes are inside obstacles. For example, the forklift, dumpster, crates, and shelves are on top of some of the nodes. Those nodes are effectively nonexistent because they're always blocked.

Hammer view of Area 9800 Landing Zone without propsHammer view of Area 9800 Landing Zone with props

In this picture, the marines have places to stand and the nodes aren't blocked by obstacles. Since the marines aren't allowed under the shelves or past the forklift, there are no positioning hints on the right. If there were, the marines could choose to stand there and try to walk where they can't. This is an example of a good layout for AI nodes.

In a game like Swarm Director 2 that depends heavily on AI, a good node graph is very important.

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Reactive Drop 1.10
Alien Swarm

Reactive Drop 1.10

Oct 8, 2014 Alien Swarm: Reactive Drop Full Version 0 comments

New weapons, bug fixes, map fixes, jump_jet_trigger for mappers etc. Extract to <path to steam>\SteamApps\sourcemods. Restart Steam

v1 Full
Alien Swarm

v1 Full

Jul 4, 2014 Swarm Director 2 Full Version 2 comments

The first release of Swarm Director 2! Adds navmesh support, several community campaigns, better marine AI, a more powerful AI director, and a new game...

Reactive Drop 1.09
Alien Swarm

Reactive Drop 1.09

Jun 21, 2014 Alien Swarm: Reactive Drop Full Version 1 comment

Full 1.09 version. Recommended for those who didn't have Reactive Drop installed. Extract to <path to steam>\SteamApps\sourcemods. Restart Steam

Patch 1.08 to 1.09
Alien Swarm

Patch 1.08 to 1.09

Jun 21, 2014 Alien Swarm: Reactive Drop Patch 0 comments

Extract this patch on top of 1.08 version. Added support for 7 bot marines. Added displaying of 7 marines in lobby screen.

Lambda Wars 2.3.6 FULL EXE
Alien Swarm

Lambda Wars 2.3.6 FULL EXE

Jun 9, 2014 Lambda Wars Full Version 13 comments

Install Instructions: 1. Run the Installer and follow the instructions. 2. Restart steam. 3. "Lambda Wars" should now appear in your games list. If you...

Lambda Wars 2.3.6 FULL 7z
Alien Swarm

Lambda Wars 2.3.6 FULL 7z

Jun 9, 2014 Lambda Wars Full Version 2 comments

Install Instructions: 1. Extract contents into your sourcemods folder (default location: C:\Program Files (x86)\steam\steamapps\sourcemods). 2. Restart...

Post comment Comments  (10 - 20 of 184)
Flash112 Jun 1 2011, 7:30am says:

can you play this in singleplayer as well? because my internet really sucks a$$... :(

+1 vote     reply to comment
tschumann Jun 17 2011, 12:04am replied:

You can add bots. I think the command is cl_addbot and you need to give two integer arguments (slot and class I think).

+2 votes     reply to comment
geotavros May 6 2012, 2:27pm replied:

incorrect, cl_selectm 0 2 adds a bot, where 0 is character id, 2 is slot. It stands for "client select marine". To remove bot, cl_dselectm 0, where 0 is character id, from 0 to 7.

+3 votes     reply to comment
KEVLAR60442 Mar 6 2011, 6:39pm says:

...and then people stopped playing all of a sudden...

+11 votes     reply to comment
SlayerX3 Nov 8 2010, 7:50am says:

I wish there were a Aliens 2 and a Warhammer Space Hulk mods for this game

+4 votes     reply to comment
NoiseChampion Feb 10 2011, 1:19pm replied:

nosm0ke is making a Warhammer 40K mod. It is still in the works though

+2 votes     reply to comment
masternerdguy Nov 20 2010, 7:10pm replied:

this is as close to aliens as you can get without Fox coming after you for copyright infringement. They have sent cease and desists to every Alien themed mod project I've ever encountered.

+3 votes     reply to comment
█Black/Brunez█ Nov 26 2010, 8:05pm replied:

That would be really awesome dude! But I wonder that Blizzard would try to **** up the mod because of copyrights...

+2 votes     reply to comment
uthere1 Mar 19 2011, 3:13pm replied:

if theres no money being made off of the mod then theres no real copyright infringement. besides we're talking about a mod, its a little bananars to go copyright crazy over a mod even for a big company like blizzard.

0 votes     reply to comment
masternerdguy Jun 12 2011, 6:34pm replied:

thats incorrect. at least in the usa copyright infringement is still infringement even if no money is involved.

+2 votes     reply to comment
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Alien Swarm
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Released Jul 18, 2010
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Highest Rated (4 agree) 9/10

The fact that this game is free continues to amaze me. Alien Swarm is a top down shooter that feels like futuristic Diablo II to a large degree. You fight off hordes of aliens with your friends in order to complete missions that require teamwork skill, and sometimes a little luck. The game has RPG elements – you level up and get access to new gear, there are four character classes, and multiple characters within those classes to select. This game should be a popular addition to any LAN party or…

Aug 29 2011, 12:04am by Rodman49

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