I wrote this function for myself because I create a lot of PowerPoints. Sometimes I plot some data, show old insufficient models, then I want to show how much better my new model is. I use grayout(h) as a simple command to wash out the old models, allowing viewers to focus on my new model while still being able to see the washed-out old models for reference.
grayout(h) lightens objects given by the handle(s) h.
grayout(h,beta) lightens or darkens objects by a factor of beta. If beta = 1, the object becomes white. If beta = -1, the object becomes black. Default beta is 0.5.