# Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?

• Your question is very difficult to understand, as it is unclear what you're asking. Can you phrase your question more clearly? – Shivam Sarodia Apr 6 '14 at 15:47