Question

I’m importing 2 models in Java3D, scaling them down and then rotating one of them using a RotationInterpolator

However, this rotates the object around the origin. I want to rotate the object around ITS centre, not the scene’s. Put simply, I want it to spin in place.

How do I rotate around a specific point?

    TransformGroup rotateTheBlades = new TransformGroup();
    rotateTheBlades.setCapability(
                  TransformGroup.ALLOW_TRANSFORM_WRITE);

    Alpha rotationAlpha = new Alpha(-1,5000);

    RotationInterpolator rotator =
        new RotationInterpolator(
          rotationAlpha,rotateTheBlades);

    Transform3D abc = new Transform3D();
    abc.rotZ(Math.PI/2);

    rotator.setTransformAxis(abc);

    rotator.setSchedulingBounds(new BoundingSphere());

    rotateTheBlades.addChild(rotator);
    rotateTheBlades.addChild(theBlades);

This is my code for doing my current rotation.

Answer 1

DR answered with translating the object to the origin, performing the rotation, then translating the object back to its position. Which worked.

My actual solution was to simply centre the model at the origin in the .obj file I was loading into Java3D, perform my rotation, and then translate the objects to their proper position.