Capsules orientation

[liyixinhua]

Hi,
I want to apply a force that is pointing forward from the perspective of the capsule body.
So how could I transform a force in capsule's local coordinates to global coordinates. Currently, I am using CapsuleX.
For example, suppose that I want to apply a force of 2 units that pointing forward.
Vector3f localforce= new Vector3f(0,0,2); //Is this local force's direction correct?
Transform t=new Transform();
t=body.getMotionState().getWorldTransform(t);
//transform the force from local coordinates to global coordinates.
Vector3f globalForce=new Vector3f(0,0,0);
globalForce.x=localforce.dot(new Vector3f(t.basis.m00, t.basis.m10, t.basis.m20));
globalForce.y=localforce.dot(new Vector3f(t.basis.m01, t.basis.m11, t.basis.m21));
globalForce.z=localforce.dot(new Vector3f(t.basis.m02, t.basis.m12, t.basis.m22));
body3.setCentralForce(globalForce);

What's wrong with the above code? It seems that sometimes the force is perpendicular to the capsule body instead of pointing forward.
Thank you very much.

[STTrife]

not sure what is wrong with your code, but maybe it's easier to do something like

Code: Select all

btTransform t;
body.getMotionState().getWorldTransform(t);
t.setOrigin(new btVector3(0,0,0));

btVector3 localForce=new btVector3 (0,1,0);
body.applyCentralForce(t * localForce);

[liyixinhua]

not sure what is wrong with your code, but maybe it's easier to do something like

Code: Select all

btTransform t;
body.getMotionState().getWorldTransform(t);
t.setOrigin(new btVector3(0,0,0));

btVector3 localForce=new btVector3 (0,1,0);
body.applyCentralForce(t * localForce);

Thanks! The problem is that I could multiply a transform with vector3f in java.