Issue of control with kinematic object

[gautam]

Hi,

I am setting a body to be kinematic object and trying to set its motion. But I am not able to make it move at all. This is the code I have to try and make it move

Code: Select all

void GameObject::Update()
{
	if(m_Body->isKinematicObject())
	{
		btVector3 translate(5.0f, 0.0f, 0.0f);
		m_Body->translate(translate);
	}
	
	float m[16];
	btDefaultMotionState *state = static_cast<btDefaultMotionState *>(m_Body->getMotionState());
	state->m_graphicsWorldTrans.getOpenGLMatrix(m);
	m_Model->SetTransform(m);				
}

I would like to know if I am doing something wrong here with the Kinematic object because it seems to have no effect on the object.

Thanks
Gautam

[gautam]

Hi

Thanks I got this working. Apparently I was under the impression that motion state gets set internally but that isn;t the case.

[gautam]

Hi,

Now I am having a few more issues with the kinematic objects. I was under the impression that although the kinematic object can be user controlled I should be able to still collide with other objects - static or dynamic. However the object seems to just pass through. Am I wrong in thinking that in case of kinematic objects the physics will take care of collision.

Thanks

[Dragonlord]

Yes and no. Collisions are still done on kinematic objects but like dynamic ones they can fall asleep ( and collisions on two sleeping bodies are not monitored ). Hence moving them around doesn't wake them up.

body1->setActivationState(DISABLE_DEACTIVATION);

takes care of this ( at last it did for me )

[Erwin Coumans]

It's best to disable sleeping during motion of kinematic objects indeed.
You can see an example of kinematic objects in CcdPhysicsDemo, if you enable the #define at the top of the demo.

Let me know if there are still have problems,
Erwin