# What is the inuition behind the radiation view factor reciprocity?

I have known that the view factor reciprosity is that

Ai x Fij = Aj x Fji

But i can't intuitively explain the logic behind this, i do know that the view factor Fij is the portion of the radiation emitted by surface i that is recieved by surface j

I have looked up for the proof but that doesn't seem to help much

Thank you

• I haven't found a good, physically intuitive explanation either. What i do know is that if you consider the double area integral definition of the view factor, $F_{ij}A_{i}$ produces the exact same integral as $F_{ji}A_{j}$ because the order of integration is reversible.
– Paul
May 12 '17 at 16:02