Dear Radiance Community,
I’m trying to gain a deeper understanding of how indoor daylight studies are carried out. Assuming there are no optimizations such as irradiance caching, would the following be true?

With perfect, mirrorlike specularity, we could simply consider energy losses due to reflectance to arrive at the final result:

For 100% diffuse materials with no specularity, we need to cast secondary rays to understand the radiance values at the intersection point

We need to repeat this step for each ray as long as one of the 2 conditions are satisfied:
 we reached the maximum number of allowed bounces
 the ray hit a light source
Now, how much radiance does each of these indirect rays have? Do each of them inherit 100% of the parent radiance, or is it divided by the amount of diffuse rays cast from a given intersection point? In the following example, would each of the blue rays carry 2.000 lx, or assuming 10 rays, would each of them carry 200 lx?
How is the illuminance at the sample point calculated? Is it a sum of values from all outgoing rays divided by the number of rays?
Is the amount of secondary rays cast from each intersection point always the same, or should it be gradually increased/decreases with each subsequent step? Are there any rules of thumb for what makes a ‘good’ amount of rays to begin with?
I’d appreciate if you could help me understand this process better!
Thanks,
Mariusz