I'm getting the hang of the tracking system but I'm not quite there yet as I'm missing some important steps.
My goal is to add the poster onto the green screen poster in the subway car and mask out the people in front of it.
The tricky part is tracking the poster without actually tracking the poster due to many obstacles going in front of it. I will have to rotoscope em through mocha and follow this video. But damn, no closed caption. I'm deaf so I'm missing a lot of information so I'm doing the best I can to follow the mouse. https://vimeo.com/79146660
Once I'm done tracking the poster, what's next? I am struggling to figure out how to apply the tracking data to the null object in AE. But I'm missing a step since it's not coming out the way I want it to be. I tried corner pin effect but it is limited to 4 corners. I tried mocha shape but it is not the shape of a poster.
Since the actors head is most likely getting in front of your tracking area, a good solution would be to move the "search shape" down to the left (the doors are on the same plane, so should be able to give a good track). Be sure to avoid reflections.
The best way to test is create a layer and draw a shape around the doors and other "co-planar" areas. I have uploaded a image for you.
Next display your Surface tool (blue box) and position this where your insert will go.
Turn on perspective and track. You should get a lot better results than dealing with the area behind the moving actor.
You should not break up the clips into segments. Instead create a track shape on your green screen...
When the actor gets in front, stop the tracker and move the shape so it avoids the actor. You can also create a new shape on the same layer using the X+ button.
The general method for this type of shot is to intelligently stop track, move search area to areas that are on same plane, then continue track.
If done correctly this is a very unique and easy to use "offset" tracking method when your track area gets obscured. When done correctly you will see the surface stick to the wall, even though the shape has been animated to capture various sections of the same plane.