Havok physics engine, can it simulate parrying?

[babywax]

I think there will be a lot of mods trying to implement melee weapons (trying, I'm sure it won't be too easy), does anyone know if the engine is fast enough and accurate enough to simulate the effects of parrying (blocking) accurately in real time, with all the forces taken into account?

 

[Brian Damage]

Quite probably. The physics are accurate down to 1/32nd of a unit. Depending on how large you make your units, you should be able to pull it off .

BTW, it should actually be fairly easy to make melee weapons, as the basic code (the crowbar) is already there. Someone from VALVe (Gabe, I think) has said that the crowbar is an actual physically-simulated bar.

Hope this helped.

 

[babywax]

Cool, thanks a lot! That's neat, the crowbar being a real bar I mean.
It will still be hard to make a good attack system that gives you control over how to use melee weapons though.

Edit:
I forgot to ask, can the havok rag doll restrict player's joints so they react like real shoulders/elbows/knees etc?

 

[Konfuzzyus]

I would think that you can restrict a joints movement spectrum in havok, I think i never saw a goon with heavily disallocated limb placement in Max Payne 2 after he ragdolled...

But about that parrying thing... I suppose this would require the engine to be able to interpolate animation data (swinging the crowbar) with physical correct movement (the impact and stuff)... I do not recall having seen something in the hl2 demos or max payne to resemble this fact (it would imply that the animation-clipping-with-wall-errors would disappear completely, and that is unfortunately not the case (at least not in max payne)...)

But if it IS faisible... *drool*

 

[Varg|Hund]

Hahaha! Taste my sword, foul knave!
WHAT? I'm just getting into character

Someone from VALVe (Gabe, I think) has said that the crowbar is an actual physically-simulated bar.

Aye, I heard that too.

 

[theGreenBunny]

But about that parrying thing... I suppose this would require the engine to be able to interpolate animation data (swinging the crowbar) with physical correct movement (the impact and stuff)... I do not recall having seen something in the hl2 demos or max payne to resemble this fact (it would imply that the animation-clipping-with-wall-errors would disappear completely, and that is unfortunately not the case (at least not in max payne)...)

I was thinking this too when I first read that quite some time ago. The strider's legs use inverse kinematics to move correctly even on uneven terrain. Maybe this technique is also used for the crowbar animation. If not, I have no idea how it could be done..

 

[dawdler]

As a fun note, even Gothic II has physically reacting swords/weapons, and it doesnt even have a physics engine

 

[Majestic XII]

Originally posted by dawdler
As a fun note, even Gothic II has physically reacting swords/weapons, and it doesnt even have a physics engine

I really hope it do have a physics engine, since it would be alot more fun if you could run around and jump and things like that

Anyways, I asked Gabe a long time ago about this and he said yes, that will be possible.

I will have "physiclized" melee weapons in my mod, so i really hope its true

 

[dawdler]

Originally posted by Majestic XII
I really hope it do have a physics engine, since it would be alot more fun if you could run around and jump and things like that

Anyways, I asked Gabe a long time ago about this and he said yes, that will be possible.

I will have "physiclized" melee weapons in my mod, so i really hope its true

Its a simple physics "engine", nothing like HL2. Weapons do react to each others blade, arrows bounce of rocks and land on the ground and stuff like that. But you cant REALLY interact with stuff physically. I dont know if that ever will work with an true RPG with the mapsizes of Gothic II, the world is simply too vast and can be affected by too many individuals.

 

[The Dark Elf]

Originally posted by dawdler
Its a simple physics "engine", nothing like HL2. Weapons do react to each others blade, arrows bounce of rocks and land on the ground and stuff like that. But you cant REALLY interact with stuff physically. I dont know if that ever will work with an true RPG with the mapsizes of Gothic II, the world is simply too vast and can be affected by too many individuals.

While I'm not too fussed about arrows bouncing off objects, I would like to see some oomf in the use of swords and axe's.. I'd love to be able to include the ability to just knock an enemy or five flying with one swing of some fancy axe then run like hell before they get up and give chase

 

[Konfuzzyus]

Hmm... I'm not too convinced about that strider-legs-thingy... If you can access the skeletal animation system of a model at runtime its quite easy to rearrange the bones according to the surface below (although i must admit it looks damn cool). I seriously doubt valve found a way to create an animation system based on forces applied to joints (e.g. so animation is created similar to reality: by appling tension to a muscle, resulting in an acceleration of the limb and a timed counter-tension which halts the limb in the desired position). This would give us real neat interaction with the world (stumbling, crushing into people, realistic jumping animation...) but would result in movement problems... you'd need something like a movement sythesizer that is able to create movements like getting up from the floor, or removing your leg from a gap in the floor from scratch... otherwise lots of people would get stuck around poles, gates and beneath boxes... Not to mention the headaches the animators will get while trying to tweak the muscle tension phases for the draw-gun-animation...

 

[Stigmata]

Originally posted by Konfuzzyus
Hmm... I'm not too convinced about that strider-legs-thingy... If you can access the skeletal animation system of a model at runtime its quite easy to rearrange the bones according to the surface below (although i must admit it looks damn cool). I seriously doubt valve found a way to create an animation system based on forces applied to joints (e.g. so animation is created similar to reality: by appling tension to a muscle, resulting in an acceleration of the limb and a timed counter-tension which halts the limb in the desired position). This would give us real neat interaction with the world (stumbling, crushing into people, realistic jumping animation...) but would result in movement problems... you'd need something like a movement sythesizer that is able to create movements like getting up from the floor, or removing your leg from a gap in the floor from scratch... otherwise lots of people would get stuck around poles, gates and beneath boxes... Not to mention the headaches the animators will get while trying to tweak the muscle tension phases for the draw-gun-animation...

I don't think the animations use muscles to move bones. They use bones to animate the muscles... sort of.

The way the strider animates doesnt apply forces from the joints, but TO the joints. The speed of the movement is irrelevant to the weight of the bones or the size of the muscles involved, it just bends the joints at predefined speeds. When the joints move, the muscles are moved accordingly.

What you're talking about would require some HEAVY development time, and a lot of patience and skill. Valve hasn't done it, but if I remember correctly some people at MIT or another university have developed a sort of self-animating 3D human model (a computer model, not a robot ) that learns how to move by itself, by applying tension to muscles. Over time, it learns to walk, jump, and walk a balance beam.

But anyway, the Strider does self-animate, just not in the way you're thinking of.

 

[Konfuzzyus]

Originally posted by stigmata
The way the strider animates doesnt apply forces from the joints, but TO the joints. The speed of the movement is irrelevant to the weight of the bones or the size of the muscles involved, it just bends the joints at predefined speeds. When the joints move, the muscles are moved accordingly.

I don't know if I am getting this right, what you are talking about is ye good olde keyframe animation system every animator uses in our days, isn't it, what has that to do with striders moving their legs according to the floor geometry (other than the fact that every 3d-mesh out there is animated like that)?

What you're talking about would require some HEAVY development time, and a lot of patience and skill. Valve hasn't done it...

I'm aware of that:

I seriously doubt valve found a way to create an animation system based on forces applied to joints

So i'm asking again: HOW is this strider animated? Is it just some overboarding script scene, where every movement is prerendered or have they used a clever way of mergeing physics with predefined animations and in what ways could you use this for Mods?

 

[theGreenBunny]

Inverse Kinematics is the tech

The game calculates where the strider should put it's leg, and the model's 'bones' move using an inverse kinematics algorithm.

 

[Konfuzzyus]

Thanks, so there's no miraculous new physics algorythm...

e.g. no parrying can be "simulated" by the engine, it can however try to create realistic looking animation phases ("emulate it") if you manage to code your melee (with attacks and parries) accordingly...

 

[Stigmata]

Physically simulating parrying could be done with the engine. While IK creates on-the-fly animations, the Source engine also supports Inverse Dynamics, which if I remember correctly is essentially the same as IK except the animations can be halted or obstructed by game objects. So essentially its physically-collidable IK animations, which is exactly what sword parrying would require.

 

[babywax]

Excellent, I plan to use IK to create sword movement so it would have to be done real time.