Chris Xiao - Compositing Demo Reel - 2024

Shot 1 - Wall Replacement

This is my first VFX Shot ever.

I added graffiti to a wall and a glass ceiling using a camera tracker and projection in Nuke. To enhance the scene, I wanted to add a water-damage texture to an irregularly curved concrete surface on the right side of the screen.

One of the technical difficulties I encountered in this part was that although the camera track was solid, there were no valid track points on the irregularly curved surface, so I couldn't directly create a card on a track point. Even if I could, the card would be flat and misaligned, needing adjustments to match the curvature of the surface.

I began by roughly positioning the card and projecting the water-damage texture onto it. By playing the shot back and forth, I observed the parallax and motion to determine which parts of the card were misaligned. By doing this, I can know which point on the card is in front, behind, above, or under the actual surface. I repeatedly adjusted the card in the 3D view until achieving a pixel-perfect result.

Additionally, all the new elements were shuffled into their own layers so they could be adjusted independently as needed.

Shot 2 - Rig Removal

When I first tackled the scene, I knew it would be challenging, but I didn't anticipate just how intricate it would get. One of the first issues I encountered was when the rig passed in front of the wall lamp. It sat right in the middle of the light bulb, causing the surrounding area to darken. This subtle change in lighting had to be corrected meticulously. I removed the rig and restored the light and lens flare, ensuring they remained consistent with the original shot.

A few frames later, another challenge presented itself. The actor's left shoulder and the rig partially obscured the light bulb, necessitating a precise dimming of the environment. The lighting needed to be dimmed to the point where only the actor's left shoulder passed over the light bulb, rather than both the shoulder and the rig. Without a reference for this specific lighting, I had to use my creativity and technical prowess to create the appropriate effect.

Moreover, the actor and the rig were in the middle of accelerating, creating significant motion blur. This resulted in a complex blend of the actor’s left shoulder, hat, and the rig. I had to reconstruct a larger area and create the correct motion blur for the actor’s shoulder and hat, maintaining the shot’s natural look and feel.

Near the end of the shot, the actor and rig moved so fast that the rig became nearly invisible, yet still perceptible. I removed the heavily motion-blurred rig and its buckle entirely, making them undetectable, and then reconstructed the actor’s motion blur to match.

Throughout the shot, I also had to remove rig reflections from the smooth background wall and window frames. Additionally, I corrected the actor’s clothing, eliminating any deformations caused by the rig’s drag.

This process was incredibly challenging, but each step was an opportunity to push my skills further and ensure the final product was seamless.

Shot 3 - Logo Replacement

I did lots of manual tracking using Mocha Pro for this heavily defocused shot.

When an object gets defocused, it is hard to see where its edge is, but its center should always be at the same place. I rendered the text when it was in focus, then inserted the clip in Mocha, and used the text as a reference to adjust the track. When the shot defocus level gets stable, there are some stable patterns that are also helpful to improve the tracking.

This concept is also helpful in finding the right defocus level. I merged the same render on top of the plate and adjusted the defocus to match the plate.

To find the defocus level for the “station” text on the screen left, I manually tracked and stabilized the area, held the frame right before the defocus started, and animated the defocus according to the plate. By doing that, I noticed a gradient mask was needed for the defocus for accuracy. I applied the same defocus to my new elements. So that, I can ensure the defocus of the “station” text is correct.

I also brought back the actress's hair and integrated it with my new content.

Shot 4 - Digital Makeup

Mission: Impossible – Dead Reckoning Part One

In this shot, Simon Pegg shook his head vigorously and this caused the lighting changes on his face. This makes smart vector tracking challenging. Especially the top of his forehead repeatedly moves in and out of the top edge of the screen. This incoherent information makes it impossible to use one smart vector or multiple smart vectors in the normal way to track this part.

I needed to lower his hairline and add some hair to the top and sides of his forehead to make him look younger. My solution is still using multiple smart vectors, but the sources of the smart vectors are the original plate and the plate played backward. I made adjustments to stitch together the movement of the new forehead hair so it looked natural and coherent.

For his beard treatment, I used a combination of keyers and rotos with vector distorts and data detected by curve tools to ensure that the major treatment was only on his faded beard but not on the skin between the beard hairs or the beard in good condition. I applied the same technique to smooth the skin on his neck, treating only the aged areas and preserving the skin that had not yet aged.

When removing the wrinkles and grooves of varying depths on his face, I filled them in while retaining detail and texture. I also matched lighting changes caused by his head movement. In the final stage, I slightly dissolved some of his wrinkles back from the plate to preserve his characteristic facial features.

I also slightly lifted his earlobes, narrowed the tip of his nose, and fixed the drooping of his left eyelid and eye corner.

Shot 5 - Articulate Roto

This roto shot was completed in Silhouette.