Ragdoll Physics Demonstration


Jul 3, 2003
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Hey all,
Pretty new here myself but I haven't seen much about the Havok system which as far as I know powers the famous 'ragdoll physics' behind the AI combine soldiers. This isn't strictly HL2 related but it gives you a good look at how the bodies react (as there were only a few brief clips in the 600 MB gamespy version - grenade explosion and the guy being shot from the tower). Anyway, found a good AVI showing this off at the official Havok site:


Have a look - quite interesting...good soundtrack too ;)

Cya round in the forums

- Tommmo
Ragdoll Physics

Hey Tom...m...mo...
welcome to the forums! I just finished watching Fallguy, and I must admit I feel sorry for the virtual stuntmen. "No Rest/No Praise/No Pay". Funny you bring up ragdoll physics, because I was just thinking that the system has problems. I was watching the Half-Life 2 demo video (again) and I saw what looked like a painful death sequence - in a yoga fashion.




These clearly show the poor combine soldier crumpling over into what was known, in my gymnastics class so long ago, as the "bridge" maneuver. That is, he was shot backwards far enough to shove his face into the ground while his feet retained contact with the floor. The rest of his body just arched. Weird.
Its just a little physics glitch with the havok engine. Its not like it is immposible to in real life when someone dies. It happens.
Re: Ragdoll Physics

hehe...those stuntmen...yes, the system definately has pros and cons. I haven't made up my mind whether to give it a stamp of approval or not, but the point of the video you examine does indeed highlight very weird movement, but thats only to be expected I suppose: think about the thousands of position combinations that a body could fall in, the system can't manage it perfectly every time. However, I'm not complaining, as the system can only be described as innovative - quite groundbreaking stuff compared to the 'canned death' sequences that we still inexplicably see in many new games today. I think that all in all its going to make the game more interesting, as you really can see the enemy bodies react to your shots. I'm a bit worried about the clipping issue personally - in a few of the sequences where the AI has been thrown about or generally beaten up there's bits of them sticking through scenery around them...again, see E3 footage again ;) any other observations on the ragdoll system?
hope to post more and start annoying people with inane observations soon .......

- Tommmo
Hmm..i belive the legs should have kicked out if he had any pain receptors :p
Yeah, that's true, though if I was being shot I would want to throw myself backwards to die with dignity. If you're going to watch the strange death sequence, it's at 13:05 and 13:11 (minutes:seconds). The problem with ragdoll physics is that the people don't have centers of gravity. They just become limp.

EDIT - and they don't act like people being shot - EDIT
They certainly aren't quite human, although they must be doing something right...I heard Remedy just subscribed to the cause now to use the technology in Max Payne 2 - all in all I'd rather have the ragdolls than canned death....plus it would be incredibly difficult to orchestrate the programming of all the various possibilities of AI snuffing it. The whole system's built around an environment that requires very little scripting to determine such settings once its finished. Imagine how long it would take a level designer to code how a body would react after falling from such a height :cheese:

- Tommmo
My Favourite Demo

I like this one, the cubes react really realistically. One thing i like about Havok is all of the fallout effects that are possible - the pool game features top spin, side spin etc. but none of these were programmed, only fallouts of the physics engine :D
I wonder if you can make mini golf with HL2. Lol. I'm just being imaginative. :)
would be even cooler if different clothing was made of different material.

like the boots is rubber, so the body should just stop if the feet hits the ground in front of the body.

btw, there's a fun game involving ragdolls called "porrasturvat". you just push a guy off a set of stairs. the more damaged caused, the more points you get ;]

find it at gamehippo.com
It's a cool game, some people think its too violent...
Problem with such advanced physics systems is that I suppose the critics of violence in games are going to have a ball when they see how realistically you're gonna be able to shoot/maim/generally injure organisms in a whole new way ;)

btw...thanks to Murray_H, those cubes rock! sweet demo

- Tommmo

*edit* wow....just found porrasturvat and can see how people really wouldn't like it! kinda cool for an interactive ragdoll - not sure about the crunching bone SFX though! :eek:

Hmm, i thougl hl-2 had a edited havok engine and when the person died they would fall and collapse into each other such as rainbow six 3, this really ruiend the game as the rest was so realistic, but that was the karma engine this is havock and i headed its been edited so that dosent happen, i am unsure but time will tell
One thing that I don't like with the current Havok system is that, as it has been mentioned, bodies seem very very limp, almost without weight. They seem exactly as the name implies: like ragdolls. Yet, humans are not ragdolls, we are much heavier than them and therefore react quite differently when gravity pulls us to the ground. We are much heavier, and different parts of our body have more weight than others.

Still, it is a great improvement over any other current games out there now, and it still is quite impressive to see it at work. Perhaps, however, Half life 3 will incorporate an even more advanced Havok engine which takes into account the things that I've mentioned.
Awesome video.

Imagine Havok Physics with SOF's gore. <winces> Damn!