Turn on mesh renderer when cam is looking.

how would I make a object mesh renderer enable when came is looking at the cube, but the mesh renderer is not enabled at the time?

Unity has something called “frustrum culling”(i think) . If an object goes out of veiw it dosent render it anyway so there is no need to do this, but look at this - Unity - Scripting API: MonoBehaviour.OnBecameVisible()