@Override
    public void write(JmeExporter ex) throws IOException {
        super.write(ex);
        OutputCapsule capsule = ex.getCapsule(this);
        capsule.write(plane, "collisionPlane", new Plane());
    }
Creates a plane Collision shape
@param plane the plane that defines the shape
jme3-jbullet/src/main/java/com/jme3/bullet/collision/shapes/PlaneCollisionShape.java