Isolating Stray Light Contribution
Each Analysis Surface and Detector Entity has the ability to filter the rays that contribute to the calculated quantity. This is shown at the bottom of the next image in the section called "Ray Selection."
There are many options to chose from:
A very simple way to isolate the stray light contribution in an imaging system (where no scatter is present) is to append a Ray Filter "Specular Ancestry > 0." Thus the designed optical path will be ignored when processing the calculated quantity (e.g. Irradiance). You can append filters by right-clicking in the list area.
The two pictures below show an Irradiance plot of an imaging system first with and then without the Specular ancestry > 0 filter.
Alternatively, if you wanted to isolate only the scatter contribution you might want to add the Ray Filter "Scatter Ancestry > 0."