Before & After

• 

• 

Alpha

Script

• 

I used Keyer to remove the green screen for core matte. And then IBK was used to remove the green screen for the edge, and then merged them together. But there is still green on the hair, so I used Keylight to despill it.

I don’t want to remove all the green for the whole plate, but only the hair. So, I roto the head out to allow the Keylight only affects the hair area.

In the beginning, I couldn’t figure out how to connect the nodes. I didn’t use Copy node but I merged, which caused my alpha look like below.

And when I merged with background, the roto was black. And I deleted the roto and just used Keylight, my background won’t show up because the alpha is wrong. I checked Gonzalo’s node and realized I should copy the alpha to the plate after the Keylight. Then it finally works.

After I merged with core matte, the alpha is correct.

Last step is to add background, I tracked first so that the background with move with the foreground camera. The object I tracked was covered by his arm in the middle of the plate, so I had to offset the tracker to track something else without moving the original track point.

I also reformat it and color graded.

Final Compositing

Firstly, I undistorted the shot with lensDirstortion node. I used the lens grid to detect the distortion and solved it. It’s very important to undistort the scene because there is always lens distortion with modern cameras, and there is no lens distortion for the cameras in Maya.

I tracked the scene and solved it, exported the scene+. After I got the camera and scene, I created sphere and planes as reference in 3D space to see how my tracking works.

Once I make sure the tracking is good, I exported the camera and pointclouds into Maya as FBX files.

I added a red highlight for the background so that it matches with the red light of the picture.

Firstly, I used keyer to increase the contrast of the alpha. And then I used grade node to add red to the highlights, I masked to the keyer so the alpha is like a mask. Then the color correction will only be applied to the white areas of the alpha. And then I added blur to soften the edges of the alpha mask.

After tracking the scene, I need to mask out the wall so that the CG machine will be inside the room.

Remove Markers and Add Scar

Script

The first thing to do is to denoise the plate so that it is easier to track the markers.

Removing Markers

And then I tracked the markers on his face in Mocha Pro. I actually tried to track in Nuke, but it cannot be tracked very well, I think it’s because the markers are too small to track. It tracked much better in Nuke, and then I exported into Nuke.

I ctrl drag the set key icon next to the translate, rotate, scale, and center tabs of the Tracker node to the exact same tabs of Roto node. Then the roto can follow the movement of the tracking information.

I used the Inpaint node to remove the markers with one click, it automatically removed and blended the spots I masked out . After removing the markers, there is no noise in the spots. The next step is to add and match the noise back.

I used ReGrain node to add the noised back to the spots. Then, add alpha from the masked out spots and premultiply it to merge the grained spots with the original plate together.

Lastly, I added the same scar from Harry Potter on his face. I reformat first and masked the scar out. Since his forehead is not flat, I used Rotopaint to smear the scar along the higher part above his eyebrow. I used Framehold node to keep it from the beginning to the end. And then, I color corrected to match the color on his skin. Lastly, I merged the scar over the plate.

Final Render