If you are modelling illuminating effect, most likely you will model the system under non-sequential mode and you could look up iV.j!H7o
J@o$V- KK
Source Diode and Source Gaussian C@rIyBj1g
Jf@~/!m}'
to check if these two sources types support your source behavior. If they do then it should serve an good approximation for your light source.