LIV is fast, light-weight, reliable and supports many intensity file formats such as IES, LDT, CIB
but also ray file formats (Speos, IES TM-25, ASCII, Zemax and Lucid Shape).
With LIV you can visualize your light distribution with its interactive illumination preview.
As a bonus, this app does not track you nor collect any data whatsoever. It is also ad-free.
Enjoy !
https://asliceofcuriosity.fr/app/light-intensity-viewer/