hi hiro,

someone correct me if I'm wrong ... but
i think for the current time of animation controll if you have multiple animations... you must to have an Animation sate machine. on each animation state you can get the time elapsed and set up the total time of each animation... for a simple animation i believe that you must to use hkaAnimationControl... GDC 2005 Demo have an good example of this... if you wish.. an animation can run only one time on an determinated
time or for example for walk/run the animation may be consecutive.

I hope this help you...

Michael Guerra
an Colombian

Hey Hiro,

Michael is correct here - to do sequences of animations what you really need is some sort of state machine.

He also mentions the hkaAnimationControl, which is where I'd start on this question.
Take a look at the Animation/Api/Playback/Control demo for examples of how to use it.

That should give you some idea of how to do loop counting and so on.

Then if I were you I'd read up about state machines, animation blend trees and so on.
You might get some good resources if you search for university-level animation courses, or look on aigamedev.com.

Cormac

Hi Hiro,

Take a look at the Animation/Api/Ragdoll/ConstraintMatching demo, it uses a rigid body controller.

This kind of controller works by directly setting the velocities of the ragdoll's rigid bodies, so it doesn't actually use constraint motors.
The hkaRagdollPoweredConstraintController is the one that drives joints using motors, but I think that can be tricky to tune and get behaving nicely (it's an inherently more difficult way to control an articulated body).

That demo has some loading code too.
There are a lot of different ways to go about loading assets, which can get confusing.
hkSerializeUtil is a useful one - here's some example code for loading a ragdoll instance and some physics data:
[The important things to note are hkSerializeUtil::load() and container->findObjectByType()]

	
// Load the file
hkSerializeUtil::ErrorDetails loadError;
hkResource* loadedData = hkSerializeUtil::load(filename, &loadError);
if ( !loadedData )
{
	HK_ASSERT2(0x0badd00d, loadedData != HK_NULL, "Could not load file. The error is:n" << loadError.defaultMessage.cString() );
}

// Get the top level object in the file, which we know is a hkRootLevelContainer
hkRootLevelContainer* container = loadedData->getContents();
HK_ASSERT2(0x0badd00d, container != HK_NULL, "Could not load root level obejct" );

// Grab the ragdoll instance
hkaRagdollInstance* ragdollInstance = HK_NULL;
ragdollInstance = static_cast( container->findObjectByType( hkaRagdollInstanceClass.getName() ));
HK_ASSERT2(0, ragdollInstance, "Couldn't load ragdoll setup");

// do something with ragdollInstance

// and if there's more than one, something like this:
while (ragdollInstance)
{
	ragdollInstance = static_cast( container->findObjectByType( hkaRagdollInstanceClass.getName(), ragdollInstance ));
	
	// do something with ragdollInstance
}

// then if you're loading physics data:

hkpPhysicsData* physicsData = static_cast( container->findObjectByType( hkpPhysicsDataClass.getName() ) );
HK_ASSERT2(0xa6451544, physicsData != HK_NULL, "Could not find physics data in root level object" );
HK_ASSERT2(0xa6451535, physicsData->getWorldCinfo() != HK_NULL, "No physics cinfo in loaded file - cannot create a hkpWorld" );

// Create a world and add the physics systems to it
hkpWorld* physicsWorld;
{
	physicsWorld = new hkpWorld( *physicsData->getWorldCinfo() );
	physicsWorld->lock();

	// Register all collision agents
	hkpAgentRegisterUtil::registerAllAgents( physicsWorld->getCollisionDispatcher() );

	// Add all the physics systems to the world
	for ( int i = 0; i < physicsData->getPhysicsSystems().getSize(); ++i )
	{
		physicsWorld->addPhysicsSystem( physicsData->getPhysicsSystems()[i] );
		//for( int j=0; j < physicsData->getPhysicsSystems()[i]->getRigidBodies().getSize(); ++j )
		//{
		//	physicsWorld->addEntity( physicsData->getPhysicsSystems()[i]->getRigidBodies()[j] );
		//	//physicsData->getPhysicsSystems()[i]->getRigidBodies()[j]->getCollisionFilterInfo()
		//}
	}
	physicsWorld->unlock();
}

As for the first problem - well, setting the bodies to keyframed is definitely not the way.

You might be having some problem with converting between model space and local space poses.
Is everything set up ok with the skeleton mapper?

Cormac

Hey Hiro,

I didn't think of that, but of course if the bodies overlap then they'll be driven apart and end up in strange positions.
What you need to do is set up a collision filter.

It's actually good practice to have ragdoll bodies overlap, since that makes it difficult for scene geometry to get stuck between the ragdoll body parts.
With a collision filter you can make it so that adjacent bodies in the ragdoll won't collide with each other, but will collide with everything else.

Check out the Physics manual, Chapter 3 section 1 on collision filtering.
So you can set up a group filter, where there's a layer for ragdolls. Within that layer there's one group for each ragdoll. You divide each ragdoll into two sub-groups 0 and 1, and set no collisions between subgroups 0 and 1.
Then for instance the upper arm will be in group 1, and the forearm and chest will be in group 0, and so on.
[Hopefully this will make more sense when you've read the documentation].

I think you're right to be using the ragdoll rigid body controller rather than the powered ragdoll controller.
The rigid body controller works by setting the velocities so it gives much stiffer results, and can drive the bodies to their model space positions. The powered constraint controller only acts by setting forces at the joints so it tends to be floppier and won't keep the character upright.

If you want to tune the parameters, access hkaRagdollRigidBodyController::m_controlDataPalette.
Have a look at Source/Animation/Ragdoll/Controller/RigidBody/hkaKeyFrameHierarchyUtility.h for descriptions of the control parameters.

Does your character have a very large scale? You seem to be making some sort of gundam giant robot, but the typical values of the ragdoll controller are probably set with human characters in mind :)

Cormac

The character controller and ragdoll controller are two separate things.

m_controlDataPalette is for the ragdoll controller, allowing you to set parameters like gains for how quickly the pose error of the ragdoll will be corrected.

The character controller is a high-level object that represents your character's movement about a scene.
If you want to set parameters like walking speed and jump height then you can do that while setting up the character controller state machine.
I think we've had a couple of threads here mentioning this in the past few months.

cheers, and good luck with it
Cormac

Hey Hiro,

I'll just say - be careful with the scale of physics objects.
Because of the limitations of floating point math, physics calculations can be very sensitive to large variations in scale. Havok works best for objects that are between about 10cm and 10m - 'tennis ball to truck' scales.
It depends on the size of the rest of the objects in your game world, but you might consider scaling everything down (as long as that won't leave you with tiny objects).

As for the animation question, that would normally be done at the skeleton level.

Say you have two animations, one running and one holding/shooting a gun.
Then you have a set of bone weights for each animation: for the running animation the bones of the lower body are set to a weight of 1 and the upper body to zero; and vice versa for the shooting animation.
Then when you blend these animations together on the skeleton you get running in the lower body bones and shooting in the upper body bones.
hkaAnimationControl allows you to set per-bone weights.

Alternatively, you might be able to just have partial animations that work on a subset of the skeleton, and use hkaAnimationBinding to define those sets. This is a bit more complex than using full-body animations with per-bone weights, since there's more housekeeping to do and exporting partial animations might be trickier.

Then you use the ragdoll controller as usual to drive your ragdoll to the skeleton's pose.

Cormac