@Override
    public String toString() {
        return getClass().getSimpleName() + " [Origin: " + origin
                + "  Direction: " + direction + "  Extent: " + extent + "]";
    }
Returns a string representation of the LineSegment, which is unaffected.
For example, a segment extending from (1,0,0) to (1,1,0) is represented
by:
<pre>
LineSegment [Origin: (1.0, 0.0, 0.0)  Direction: (0.0, 1.0, 0.0)  Extent: 1.0]
</pre>

@return the string representation (not null, not empty)
jme3-core/src/main/java/com/jme3/math/LineSegment.java