Robert Downey Jr. has shared the first set photo of himself on the Avengers: Doomsday set. While it does not show him as Doctor Doom, the photo reveals there are CGI dots on his face. I hope that turns out to be for Victor von Doom's scars or the villain's hood. However, if they are being used for Doctor Doom's iconic mask, I would not really be a fan of that. I believe the mask has to feel real and tangible, and we know how MCU CGI has made characters and suits look wonky in the past.
