It can be seen that somtimes isolines are projected outside the tube-area in tube-illumination plot. Why?
We use some smoothing on calculated data at their visualization (algorithm embeded into GNUplot). In the case that at the interface border a highly illuminated area occurs, the smoothing-algorithm results in spreading of the “illumination” outside the tube. The solution is simple: set your own isolines values (in ‘Results / Graph settings’ menu) excluding very low illumination values.
