This week we are asked to roto the machine sequence. I have tried both two idea to get a correct alpha.
One of the method is easier. Only using a certain fix frame to project it on card which is at a correct position and we can get a property result by a correct render through a tracking camera. Another one is a little complex I use two project node to finish it. I think the both two way have been told in two weeks ago, so I did not explain too much here just post a screen-print.