Let us say we have 2 points A and B. The outgoing radiance at point A is dependent on incoming radiance from point B and vice versa. Does this mean we have to solve a system of equations to get the solution? If so, it gets a lot more complicated with many points.
I noticed we only consider the hemisphere. For translucent surfaces with light source behind them, do we then group that with Le or do we add another hemisphere integral?
What is the exact definition of the point of interest here?