Indirect Illumination Technics like Final Gather or/with Global Illumination provides the most realistic light contribution to your scene. There are several technics to fake that illumination, but for the architectural Visualisations, totaly unsuitable!! There is often used ies Data or elumdat light profiles, who treat the used lights as the were real world lights. This profiles are provided by the manufactorers of lights.

This was an example of the need of those Methods, because they mimic in order of proper shader use, the real world behavior of light, such as indirect light rays, color bleeding, energie contribution, caustics(a similar Shading technic), ie

And it makes smoother results and so on and so forth... but this is over the top to explain, for this thread!

I do render since a few jears and I´m really not an beginner, but this special topic is an really unknown issue of mine.
In the learning paths you can go through, there is really nothing good about that!
For that reason this secondary a question to the SM TEam!!

CAN YOU MAKE A REALLY DETAILED TUTORIA, ABOUT THAT TOPIC??? I do buy directly two of them!!

Are there any advices out there!?!??

greets!