Re: [JAVA3D] rotX and rotY

[Barry Walsh]

Hello,

 

    I have found difficulty with the setEuler(Vector3D) method. I found that it did not reflect exactly the motions that I expected, or needed to reproduce. didn't investigate very far, because I found something similar to what David Halle used. Here's what I use to get 6 degrees of motion for ship hulls.

 

           

            Motion motion = (Motion)motions.get(index);    // retrieves a single motion slice with 6 degrees....
            float roll = motion.getRoll();
            float pitch = motion.getPitch();
            float yaw = motion.getYaw();
            float heave = motion.getHeave();
            float sway = motion.getSway();
            float surge = motion.getSurge();
                      
            // STEP 2 CREATE THE ROTATION MATRIX
            // Create a matrix corresponding to roll pitch and yaw
            Matrix3f mat1 = new Matrix3f();
            mat1.rotX(Math.toRadians(roll));
           
            Matrix3f mat2 = new Matrix3f();
            mat2.rotY(Math.toRadians(pitch));
           
            Matrix3f mat3 = new Matrix3f();
            mat3.rotZ((Math.toRadians(yaw));
            
            // combine roll pitch yaw matrices
            mat1.mul(mat2);
            mat1.mul(mat3);
            
            //STEP 3 CREATE THE TRANSLATION VECTOR
            Vector3f vec = new Vector3f(surge,sway,heave);
           
            // STEP 4 COMBINE INTO ONE TRANSFORM AND SET IN HULLTG

            // an alternative would be to get the Transform from the TG and reset the values...
            Transform3D next = new Transform3D(mat1,vec,1.0f);    // 1.0f = scale..
            hullTG.setTransform(next);

 

    Just another idea....

 

Cheers,

 

B.

 

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-----Original Message-----
From: David Hall� [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 11, 2000 5:14 AM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] rotX and rotY

>If you multiply seperate rotations, the second rotation will use the
>resulting object of the first rotation.
>If however you want to do several rotations at once, e.g. roll/pitch/yaw for
>an aircraft, you should use the
>Transform3D.setEuler(Vector3d) method.

I use the roll/pitch/yaw for an aircraft (ie. a transformgroup) like this:

// T is the current Transform3D for my TransformGroup
  public void rotate(double[] rotationAngles) {
    Transform3D temp = new Transform3D();
    temp.rotY(rotationAngles[0]);
    T.mul(temp);
    temp.rotZ(rotationAngles[1]);
    T.mul(temp);
    temp.rotX(rotationAngles[2]);
    T.mul(temp);
    setTransform(T);
  }

David.