New NPC. Headcrab swarming some combine soldiers. Pretty sweet.

Posted by danbot on Nov 20th, 2009

Okay, we need to give out the "Hey I'm not dead" message. As well as answer your question of "Who the hell is this who's posting?" We'll do both of those now.

First of all, hello there! I'm danbot and I'll be the Media and News coordinator for the Triage Mod team. wilsonC, Alex, FRABAR, and the other gentlemen have been mostly cracking away at getting the gameplay down for the mod so I'll be here to post information. I'm also going to be trying to get on wilsonC's so we can have smaller, more streamlined updates.

Anyway, today we're going to post some NPC AI based off some old source tech demo. We made it cool for gameplay purposes, or so at least wilsonC tells me. It involves having a single NPC, and having it control a bunch of headcrabs, almost like limbs. I wanted more information on the topic, but wilsonC is being sly and told me "its cool because it freakin' eats people."

See the video, and tell us what you think.

Post comment Comments
ThePeanutBaron Nov 20 2009 says:

Very good work =D

+4 votes     reply to comment
cheesemoo0 Nov 20 2009 says:

Haha, that is cool.

+2 votes     reply to comment
ZombieX Nov 20 2009 says:

wow awesome

+3 votes     reply to comment
Greenagainn! Nov 20 2009 says:

Verrry nice.

+3 votes     reply to comment
Knights Nov 20 2009 says:

I lulz....

0 votes     reply to comment
Ark_ Nov 20 2009 says:

That is pretty cool nice work.

+3 votes     reply to comment
skyewing Nov 20 2009 says:

Im sure you need some kind of explosive weapon to have any chance against that.....

+1 vote     reply to comment
Ashkandi Nov 20 2009 says:

Omg zergrush!

+3 votes     reply to comment
medve Nov 20 2009 replied:

avagyte zergrush :D

0 votes     reply to comment
raidergeo34 Nov 20 2009 replied:


+1 vote     reply to comment
Metalspy Nov 20 2009 says:

Hahaha cool, I guess I would be pretty scared if those headcrabs surrounded me.

+1 vote     reply to comment
Lt.SnoWolf Nov 20 2009 says:

Needs less headcrabs. But other than that! AWESOME! Id hate to be red mist :D

+1 vote     reply to comment
Danboe Nov 20 2009 says:

That's pretty cool! :D

+1 vote     reply to comment
ZeroSen Nov 20 2009 says:

Very nice man, keep it up!

+1 vote     reply to comment
turkey72 Nov 20 2009 says:

wow, very intresting.

+2 votes     reply to comment
Gregar Nov 20 2009 says:

thats scary

+1 vote     reply to comment
Fiasco Nov 20 2009 says:

Good stuff, an original enemy attack!

+1 vote     reply to comment
Kage.Ookami Nov 20 2009 says:


+1 vote     reply to comment
Pwnd_Ja Nov 21 2009 says:

Seems very odd as the target of the swarm needs to be in the middle of said swarm before they attack. Also, they don't move individually, so it is very apparent that there is only one AI controlling them... Imo, you should aim for a finished product similar to The Director from L4D.

+4 votes     reply to comment
wilsonC Nov 21 2009 replied:

You're very observant :)
You do have to be around the swarm's center to be damaged by it, but the whole thing moves a little faster than your running speed (though not quite as fast as sprinting speed) so once they get close, you'll get swarmed pretty quickly unless you turn your back and run.

And yes, they do look pretty fake when they're not attacking, but there's never really an opportunity to see them idling since they love eating people. The advantage of having one NPC control a bunch instead of making them individuals is that it's a lot faster, and it's possible to have 50+ of these guys without lag, while about 30 regular headcrabs can get pretty slow.

As for the L4D director, it's not really what most people think it is. It's an entity that randomly spawns bad guys/guns/ammo depending on the players' situation, and it wouldn't really work for something like this.

+1 vote     reply to comment
Blandr3ws Nov 21 2009 replied:

It looks pretty cool so far and is definitely a really nice feature to have, The headcrabs that climb up the target are AWESOME.
But the fact that the current implementation has head-crabs running past the target before attacking it looks unrealistic.

It'd be better to use some simple flock AI, keeping the individual agents much simpler than the default hl2 head-crab but creating a more believable movement pattern :) The target could be used as a leader, one headcrab could be a leader and use more complex ai itself or the target could be directly weighed into the flock movement.
Try a read through of

Sorry if my advice isn't amazing, I haven't studied much AI yet.
GL anyhow, keep it up! :)

+4 votes     reply to comment
wilsonC Nov 21 2009 replied:

That site looks very helpful, thanks for the advice!
Right now how it works is the "leader" is an invisible npc that has to reach the target before it can attack. Teleporting the "leader" to their target actually sounds like a good idea, I'll try it out. Thanks again!

+2 votes     reply to comment
Jesternz08 Nov 21 2009 says:

that looks awesome haha, I bet it would look great from the point of view of the player as well.

+2 votes     reply to comment
56er Nov 21 2009 says:

loool, the endingof the video was cool.
that poof around the combine was kind of weird, but the rest is cool. Maybe you should make an animation, showing the victim of the hc, being forced to the ground, instead of just dying and falling down like a back of waste. So it looks like, as if there were fighting for there life.

+1 vote     reply to comment
willyTHERAVEGER Nov 21 2009 says:


0 votes     reply to comment
explodr Nov 21 2009 says:

Finally a swarm script. This is awesomesauce.

+2 votes     reply to comment
TheHappyFriar Nov 21 2009 says:

neat! So it's actually a single entity? Are the headcrabs all one mesh combined or are they all separate mesh's but they are all controlled by a single entity/AI (ie they're bound to "tentacles" of the AI)?

I think it would be cooler to shrink the size of the headcrabs to 1/2 that size & have swarms that big. IE Locust like headcrabs. Then have swarms with that size but less crabs. IE 5-10.

That's a really neat idea you've got there, I'm going to see if I can do that myself now. :D

+1 vote     reply to comment
wilsonC Nov 22 2009 replied:

The entity spawns a bunch of little ones that just dance around and have no AI. It is cooler when they're smaller and there's more of them, but it can be really frustrating to hit smaller headcrabs. However it's still a WIP, so things may change.

+1 vote     reply to comment
Kruk Nov 21 2009 says:

team headcrab 2 brutal, but funny like in a cartoon XD

+1 vote     reply to comment
Mualama Nov 21 2009 says:

Guy with rocket launcher:1
Everyone else:0

+2 votes     reply to comment
Eylam Nov 22 2009 says:

"It's cool because it freakin' eats people."

lol :D

+1 vote     reply to comment
Liliana_Light Nov 22 2009 says:

That's awesome.

+1 vote     reply to comment
Foda Nov 23 2009 says:

Don't take full credit for this. It's based on the npc_blob found in the default SDK.

0 votes     reply to comment
wilsonC Nov 29 2009 says:

We didn't. Read the text please.

+1 vote     reply to comment
rokitiger Jan 19 2013 says:

Just because of this I choose to get this mod :D (EXCELLENT JOB btw)

+1 vote     reply to comment
grumpy_robbot Feb 2 2013 says:

GUTS GUTS EVERY WERE! lol very cool work on the walking tho also MORE GUTS GORE STUFF LIKE THAT >:D

+1 vote     reply to comment
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