public void setYExtent(float yExtent) {
        if (yExtent < 0) {
            throw new IllegalArgumentException();
        }

        this.yExtent = yExtent;
    }
Alter the Y-axis distance between the center and the boundary.

@param yExtent the desired distance (&ge;0)
jme3-core/src/main/java/com/jme3/bounding/BoundingBox.java