Now that we have all the 3D plates ready, we need to work on the real footage that will be used in the composition, the same one we used during the tracking stage. Because we created some tracking marks to achieve better tracking on several locations, we need to remove these marks to have a clean plate for compositing. We cannot remove the marks directly by using a chroma key effect because other tones and elements need to be removed from the plate as well, so to clean this plate we are going to use the masking tool. We will start with a plate like this:

And we will turn it into something like this:

We use a very bright color to differentiate the subject from the background, so it is easier to see any artifact or problem with our mask; then we can change this color to any other background with total confidence in the quality of our mask.