Nuke Compositing, inteface and concealing tracking markers

Nuke tutorial and training with Matt Cameron!

Wow, Nuke is brilliant and I love the interface....very simple, flow diagrams, that develop a tree of nodes...and nothing at all buried or hidden.

We were given a sample of footage from 'Ratking'. The footage was of a hysterical pregnant woman, whose belly was full of writhing rats, pushing and moving under her skin.

Creepy.

This effect was achieved by placing a  'plastic' pregnant stomach on the actress.

A shadow map of moving rat feet was created, by placing real live rats on top of lycra stretchy fabric, and filming them running around from the underside.

Nuke was used to composite both the live action and shadow map sequences and included the use of tracking markers.

Our task today was to get to know the Nuke interface and to mask out the tracking markers (black dots)

 1. The Nuke Interface.
Showing imported 'read' live action footage (already including the shadow map of the running rats). The 'A' output of the 'read' footage is then connected onto a 'Tracker' node (peach rectangle ringed by the smaller red circle)
The 'A' output from the 'Tracker' node is then connected to the 'Viewer' node below.

2. We then created a 'constant' node (thin red circle with grip points), to cover the black tracker. There is the simple option of creating just a plain colour, or a cloned colour, which completely matches to the varying pixel colours. The areas ringed in yellow, show a keyframe on the timeline (left) and where it appears in the properties box on the right.

3. Using a  'background' node (as shown as a lilac rectangle) to collectively present all items clearly, that belong in a certain part of the script. This is brilliantly simple and what a great tool, especially when working in a team. The importance of labeling, and being clear when passing on the job to the next person is crucial.

 4. Adding a 'grain' node (circled in yellow below the lilac rectangle) and showing the sliding values on the right (also circled in yellow) for the RGB channels. B (Blue) seemed to show the most grain...