public void setShadowZExtend(float zFar) {
        if (fadeInfo != null) {
            fadeInfo.set(zFar - fadeLength, 1f / fadeLength);
        }
        this.zFarOverride = zFar;

    }
Set the distance from the eye where the shadows will be rendered default
value is dynamically computed to the shadow casters/receivers union bound
zFar, capped to view frustum far value.

@param zFar the zFar values that override the computed one
jme3-core/src/main/java/com/jme3/shadow/PssmShadowRenderer.java