I think to rotate about a vector, we could be using the class AxisAngle4f.
E.g: to rotate the object about a vector specified in axisAngle and the
angle
of rotate is also stored in axisAngle.
----------------------------------------------------------------------
targetTG.getTransform(rotation);
//angle to rotate
axisAngle.angle=angle;
//Translate or rotate the object to origin
//by multiplying the inverse of the original transform, backT
rotation.mulInverse(backT);
temp.set(axisAngle);
rotation.mul(temp);
// translate or rotate the object to its intended location
rotation.mul(backT);
targetTG.setTransform(rotation);
------------------------------------------------------------------------
where
targetTG,temp,backT and rotation are Transfrom3D
axisAngle is AxisAngle4f
The full code for the above behavior is here
----------------------------------------------------------------
public class MouseRotationBehavior extends Behavior
{
protected WakeupCriterion[] mouseEvents;
protected WakeupOr mouseCriterion;
private TransformGroup targetTG;
private Transform3D rotation = new Transform3D();
private Transform3D temp= new Transform3D();
private float angle = 0.0f;
private Transform3D backT = new Transform3D();
private AxisAngle4f axisAngle= null;
private Quat4f quat=null;
MouseRotationBehavior(TransformGroup targetTG)
{
this.targetTG = targetTG;
// this is where your object is located in the scene
backT.rotX(Math.PI/2d);
backT.setTranslation(new Vector3f(0.0f,-3.0f,-14.0f));
// this is where you set the rotation vector and angle
axisAngle= new AxisAngle4f(new Vector3f(0.0f,1.0f,10.0f),0);
quat=new Quat4f();
quat.set(axisAngle);
}
public void initialize()
{
mouseEvents = new WakeupCriterion[1];
mouseEvents[0] = new WakeupOnAWTEvent(MouseEvent.MOUSE_DRAGGED);
mouseCriterion = new WakeupOr(mouseEvents);
wakeupOn (mouseCriterion);
}
public void processStimulus(Enumeration criteria){
angle += 0.001f;
targetTG.getTransform(rotation);
axisAngle.angle=angle;
rotation.mulInverse(backT);
temp.set(axisAngle);
rotation.mul(temp);
rotation.mul(backT);
targetTG.setTransform(rotation);
this.wakeupOn(mouseCriterion);
}
}
-----------------------------------------------------------------
----- Original Message -----
From: "W.M.Lau" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, August 17, 2000 6:31 PM
Subject: Re: [JAVA3D] Robot Arm
> Hi, Long
>
> I am currently working on the similar project.
> My project is also trying to produce a robot arm simulation.
> May be we can team up together and share our ideas.
>
> I have only started learning java3d on my own. I 've found out that the
> question you've asked depends on the pivot point of the rotation. I think
> there is a function to set the pivot point.
>
> Also I think there is another function that allows boolean check to see
> if an object is picked up or not. Roughly If I remember right they both
> should be under Transform3D class.
>
> Sorry, I can't be much help. I am still looking for those two method
> names as well.
>
> It's possible to rotate an object manually using the keynavigator or
> mouse navigator, but I think the pivot point is set as the center ofthe
> object as default, to do this it must need to change a pivot point.
>
> Hope what I talk make sense to you, because it doesn't make much sense to
me.
> Still, if you think we should team up together, feel free to share ideas
> and method with me.
>
> yours sincerely
>
> Raymond Lau
>
> On Tue, 15 Aug 2000, Siau Tan Long wrote:
>
> > I am making a robot arm simulation.
> > I wanted the user to pick each segment of the arm and rotate about the
> > joint(given point) manually.
> > My question are:
> > Which class should I use and how do I know which segment that the user
had
> > picked?
> > How do I rotate about a given point?
> >
> >
> >
> > _________________________________________________________
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> >
> >
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>
>
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