What about the key frame blending?

  • Thread starter Thread starter Ro_Bert
  • Start date Start date
don;t download this movie, it shows you some really crapy game. RO_BERT you r lazy to put somthing like that in HL2 forums.
 
That's a demo... Not a game preview. It shows the key frame blending feature.
 
Yeah, its not a game. Dont flame without good reason.


Neway, I dont honestly know if HL2 supports this effect. It doesent look like it from the demos. But they might have included it. No-one knows except valve. Maybe you could try emailing them.
 
Its not HL2 no, but it is a effect made by havok who helped with HL2s physics engine. It could be in HL2.
 
Key frame blending is a really good idea.

For example lets say the were to use key frame blending and physics together while some one was dying in Half life 2.

It would look sort of like this, you shot a man in the head, he would reach up, grab his head and fall down using havok physics making deaths seem more realistic.

You guys remeber the death in cs or Day of defeat? well it would be like thoses death sequences combined with physics making them look extreamly realistic.

But remeber thats the wave of the future.
 
Wouldn't he just die right away and fall over without grabbing his head? If the guy is shot in the head he's pretty much dead right then and can't really do anything else.
 
Originally posted by GORGON_is_Back
don;t download this movie, it shows you some really crapy game. RO_BERT you r lazy to put somthing like that in HL2 forums.
Click to expand...

Don't expect to be back here for long.
 
lol, make one mistake and they'll eat yah alive
 
heheh, i dont like gorgon anyway. I never forgave him for his NASTY flame he gave me for no reason at all. Then he deleted it so i couldent report him. Hes a bit of a di*k tbh. But i managed to keep my cool here for sum reason. :)
 
I've e-mailed Gabe AND Erik about this and nither of them have e-mailed me back!
They havent e-mailed me back for any of my other questions either......they must be buisy or somthing.........mabie making some kind of game. I cant be totally sure.
 
Originally posted by Abom|nation
Don't expect to be back here for long.
Click to expand...
ye syes yes!

/me is sooo happy :)

oh and btw
i think HL2 has the feature, just a bit tweaked, so it doesnt take that many shots to kill them... so they wont stay up like that...thats my guess anyways
 
I think that having characters twitch and stop shooting you if you shoot them could make for some unchallenging enemies.
 
Originally posted by marksmanHL2 :)
Its not HL2 no, but it is a effect made by havok who helped with HL2s physics engine. It could be in HL2.
Click to expand...


Other way around. Half-Life 2's physics engine is Havok. Valve only did a few improvements along the way so that it could work better with their game engine. Valve didn't actually make their own physics engine.
 
I wouldent be supprised if they are a little too busy right now. I have sent them a few emails recently with no reply. But i have got replies in the past, maybe we will get lucky eventualy
 
OMG how DARE they not email back. They just dont think of the community. I say we boycott their next game, whatever it is. Whos with me?
 
I dont know........if they're next game is Pong 2...then mabie............no......they would find a way to make that kick ass....Valve is magical.
 
That video is truely awesome. It makes me sad that it probably won't be in Halflife 2.
 
Originally posted by Dark Auro
Wouldn't he just die right away and fall over without grabbing his head? If the guy is shot in the head he's pretty much dead right then and can't really do anything else.
Click to expand...

Ok the head shot example was kinda bad, here another one:

lets say some guy got shot in the gut, most of the time gut shots take a while for people to die, and it also depends on the calibur of the bullet.

When getting shot in the gut people don't just drop dead. they would grab there stomach and stumble around then fall.

Hl2 could use key frame blending to show that.
 
Originally posted by Abom|nation
Don't expect to be back here for long.
Click to expand...

i was so happy when this guy left, abom, make hudson happy again :cheers:
 
there hasnt been any effects that look like key frame blending in the videos. its just strange how shooting at the combine at the start of traptown looked a bit like keyframe blending, but turned down. However there is no evidence of this in tunnels that i can see

maybe they turned it off, who knows :/
 
Well I emailed Gabe a couple times asking if Half-Life 2 uses "ragdoll/keyframe blending." I just said "ragdoll/keyframe blending" because that's what it says in the zombie demo, but apparently they didn't know what I was asking, and that's why I didn't get a reply at first. Here's what I got:

Gabe Newell:

"Well, the first time I read your question I wasn't sure what you were getting at.

There are a bunch of different inputs that get blended together to generate a frame of animation. So there isn't really a simple yes or no answer that isn't misleading depending up on the context of your question. Yes we physically simulate model behaviors under certain circumstances. Yes we blend.

Why are you asking?"

-------------------------

Ken Birdwell:

"Yes?

I also don't quite know what you're asking. We support any number of forward kinematics (keyframe) and inverse kinematics (IK) blends, along with usually one forward dynamic (ragdoll) blend. High end humanoid characters such as Alyx can combine upwards of 20+ FK blends and around 4 IK blends, as well as their FD set, though once that's active the others usually get suppressed. Other characters are completely FD, others are IK and FD, some are everything, some are actually ID (inverse dynamics) and some are just FK. Others have odd mixes where some portions of the model are always one way, other portions of the model are always another, etc."
 
i thought that all characters where just as technologically advanced as the next... i swear gabe said that
 
Originally posted by Dagobert
I think that having characters twitch and stop shooting you if you shoot them could make for some unchallenging enemies.
Click to expand...
I've considered this myself. However, seeing them visibly react to your bullets creates a more dynamic experience than enemies that stand around like statues before suddenly collapsing to the ground in a lifeless heap. There are certainly ways you could show such a reaction without compromising the challenge. However, since Havok obviously supports ragdoll blending as a default feature, Valve most likely had a very good gameplay reason for not including it (if indeed the gameplay videos are accurate representations of the finished product. This may be a feature that they are including but it wasn't quite ready when the E3 videos were made).
 
correction sepukku is a form of Hara-Kiri

look em up... sepukku involves disembowelment
 
Ken Birdwell:

"I also don't quite know what you're asking. We support any number of forward kinematics (keyframe) and inverse kinematics (IK) blends, along with usually one forward dynamic (ragdoll) blend. High end humanoid characters such as Alyx can combine upwards of 20+ FK blends and around 4 IK blends, as well as their FD set, though once that's active the others usually get suppressed. Other characters are completely FD, others are IK and FD, some are everything, some are actually ID (inverse dynamics) and some are just FK. Others have odd mixes where some portions of the model are always one way, other portions of the model are always another, etc."
Click to expand...
I didn't understand a word of that.
 
Originally posted by Mountain Man
I didn't understand a word of that.
Click to expand...

I think he's saying "we have it all and more? I dont understand why you ask such a basic thing?" :)
 
Mountain Man, I'll try to explain it for you, but don't expect a good job of it.

What he's saying is that you can potentially blend as many keyframes (canned animations i.e. grab your face when you get hit) as you want with the IK animation*. You can also blend the IK and FK (keyframe) animation with ragdoll effects, an example of which could be a guy in midair with his legs flailing (ragdoll), grabbing his face with one arm (keyframe animation) while trying to stop himself with his other arm (Inverse Kinematics). Some enemies and NPCs support this group of blending, while others have just ragdoll and keyframe, others have just inverse kinematics, others have one part ragdoll, the other part IK, etc etc.

*Inverse Kinematics is a type of animation. Instead of using keyframes (canned animations) it tells a point on the body where it has to touch and animates the body dynamically.
Example: Instead of having a canned walking animation, the IK engine tells the body that the right foot must move to touch a point 20 inches ahead, and animates the leg and body movements required to move it. The most noticeable use of this is in the Strider. If it had a keyframed walk, its legs would clip in and out of so many objects it wouldnt even be funny.

Tell me if I'm wrong.
 
Originally posted by stigmata
Mountain Man, I'll try to explain it for you, but don't expect a good job of it.

What he's saying is that you can potentially blend as many keyframes (canned animations i.e. grab your face when you get hit) as you want with the IK animation*. You can also blend the IK and FK (keyframe) animation with ragdoll effects, an example of which could be a guy in midair with his legs flailing (ragdoll), grabbing his face with one arm (keyframe animation) while trying to stop himself with his other arm (Inverse Kinematics). Some enemies and NPCs support this group of blending, while others have just ragdoll and keyframe, others have just inverse kinematics, others have one part ragdoll, the other part IK, etc etc.

*Inverse Kinematics is a type of animation. Instead of using keyframes (canned animations) it tells a point on the body where it has to touch and animates the body dynamically.
Example: Instead of having a canned walking animation, the IK engine tells the body that the right foot must move to touch a point 20 inches ahead, and animates the leg and body movements required to move it. The most noticeable use of this is in the Strider. If it had a keyframed walk, its legs would clip in and out of so many objects it wouldnt even be funny.

Tell me if I'm wrong.
Click to expand...

I'm sorry i'm stupid.

Physics is cool.
 
Good point mate, if you shot them repeadedly in the chest, rather than them eventually fall over lifelessly, they could clutch at their heart while simultaneously falling over the rail/beam/bar/box/interesting-object and it would look very cool, but not a head shot, that should kill you straight up, no keyframes here, move along folks.
 
Actually i looked at a physics engine demo with inverse kinematics, looked excellent, sadly HL2 doesn't feature it.


Possibly moddable?
 
Actually i looked at a physics engine demo with inverse kinematics, looked excellent, sadly HL2 doesn't feature it.
Click to expand...

Uh... you read the thread? It does. In fact, if it didn't the strider vids would be next to impossible.
 
Originally posted by CommieX

Ken Birdwell:

I also don't quite know what you're asking. We support any number of forward kinematics (keyframe) and inverse kinematics (IK) blends, along with usually one forward dynamic (ragdoll) blend. High end humanoid characters such as Alyx can combine upwards of 20+ FK blends and around 4 IK blends, as well as their FD set, though once that's active the others usually get suppressed. Other characters are completely FD, others are IK and FD, some are everything, some are actually ID (inverse dynamics) and some are just FK. Others have odd mixes where some portions of the model are always one way, other portions of the model are always another, etc." [/B]
Click to expand...

CommieX, this is fantastic info, I'm glad you e-mailed them. I will try to explain Ken's e-mail:

"We support any number of forward kinematics (keyframe) and inverse kinematics (IK) blends, along with usually one forward dynamic (ragdoll) blend. "

First, the difference between the specific animation methods Ken mentioned. Foreward Kinematics are the most simple of all the methods. FK is where the animator simply defines an animation as a set of joint rotations. "Shoulder rotates 30 degrees on X axis, elbow rotates 20 degrees on X axis, etc."

Inverse Kinematics are a little more complicated, they allow the animator to define where he wants a specific rigid or elastic body to end up and the engine figures out the different joint rotations required to place the body in the desired position. "Place hand at coordinates of lever." Both IK and FK animations can have additional properties that define the acceleration of the different bodies, to influce how the animation is generated. "Start rotating quickly, then slow down as you approach the final state."

Forward Dynamics takes into account external 'real world' influences like mass, acceleration, friction, etc. An example of a dynamic problem is (as Ken points out) when a character dies and goes into ragdoll mode. The engine is determining how a set of connected bodies (arms, legs, head, etc) will be influenced by factors like inertia, collision with other objects, and gravity. I'll explain Inverse Dynamics later.

"High end humanoid characters such as Alyx can combine upwards of 20+ FK blends and around 4 IK blends, as well as their FD set"

Since IK is more expensive than FK, it's only used when needed. An example of an IK animation for Alyx might be "Look at the player". Since the player's position relative to Alyx can change, a static FK animation would not be able to turn her head appropriately. By 'their FD set' he's referring to the rules that govern ragdoll, like the extents to which each joint can rotate, the weight and center of gravity for each object, the forces acting upon the objects, and possibly things like how 'stiff' each joint is.

"though once that's active the others usually get suppressed."

Meaning, once the ragdoll is in effect (the character has died), other animations (like running) do not occur.

"Other characters are completely FD"

Here he's referring to 'characters' that have no kinematic animations. This means that all movement of the character is generated by real-time physical forces and collisions, not with any arbitrary positioning of joints by an animator. The man-hacks may be an example of this, it appears that all their movement is the result of a dynamic force that is constantly pushing them toward the player, and their animation is influenced by collisions with walls, shelves, the crowbar, etc. Certainly none of the human characters are fully FD though, they'd fall down all the time if so.

"others are IK and FD, some are everything, some are actually ID (inverse dynamics) "

ID is by far the most processor intensive of all the methods, I'm actually quite surprised and amazed that they were able to add this. ID, like IK, allows the animator to set how he wants something to end up, and then let the engine figure out how to get it there. In IK the engine simply figures out how to rotate the joints to achieve this, however, ID solves the problem by assigning forces to the various objects involved. This is a very important difference because the application of forces allows the animation to dynamically interact with the rest of the world. If a zombie's 'swipe' attack were animated via IK, it would be identical every time. But if it were animated with ID, the swipe could be interrupted by a pole in the way, or a crowbar.

This means that, depending on the limitations of their ID animation system, accurate swordplay/melee combat would probably be possible.

In relation to the Havok demo, I think what that demo is doing is blending FK animation (the zombie walking animation) with FD animation (getting shot). Ken doesn't mention anything about blending different types of animation together, so who knows. (The word 'blend' in Ken's e-mail refers to the creation of an animation of a single type I believe, not the mixing of two different animation types within a single animation) The fact that the source engine can do ID though is amazing. :D

EDIT: Clarification and spelling
 
sweet post dscowboy! I'm glad someone like you turned all that almost-indecipherable rubbish (no offense ken birdwell) into something i can understand. i could have figured it out probably but wow this is like getting the answer from the back of the book, it even shows the work. Thanks! :cheers:

-Phision
 
You must log in or register to reply here.

Similar threads

MFL
Fascinating look at the ongoing psychological evolution of flat hieirarchies.
Replies
2
Views
2K
Tollbooth Willie
Tollbooth Willie
B
From Warren Spector to Arkane Studios: Half-Life 2's cancelled Ravenholm episode
Replies
2
Views
10K
Clan Wolf 2
Clan Wolf 2
Omnomnick
Examining The Files Of "SteamVR Performance Test" & "Aperture Robot Repair"
Replies
27
Views
91K
MFL
MFL
B
The cut missions of Half-Life: Decay
Replies
2
Views
21K
Evo
Evo
B
Hostile Takeover, the lost Half-Life expansion pack
Replies
6
Views
16K
Ennui
Ennui
Back
Top