I would like to compare light sources to a perfect Lambertian source. This could be done by having a checkbox that makes a Lambertian distribution show up on the polar directivity plots. Similar to what is shown in the knowledge base article image, see below.

Even better if it also showed a RMS deviation from the ideal Lambertian distribution source on the plot.

https://support.zemax.com/hc/en-us/articles/1500005490001-Light-sources-used-in-illumination-design.