It’s a simple sup check tool. You may ask why the name Cat_Checker…

We were working at MPC on Cats at that time. The director Tom Hooper asked to VFX department to deliver a perfect match between CG Cats and live-action actors. The Rotomation department made a good job but of course in the rush not all the animations were matching. So the compositing department made a Huge work of fix with animated warping and P-Matte (I will talk about this process on a different page).

So we had to compare the portion of the screen where there was the cat with the live-action plate for every frame to match not only the shapes but also shadows and colors.  A normal wipe tool was not enough…


You can create every kind of shape that is needed for the check. Compare it in the same position or move one plate on the side to check every frame.

A super thanks to Andrea Perisano who helped me with this very useful python script to center the transform pivot in the center of the roto in one click.

Control checkbox to check negative value, normal and above one. And of course, the color check, usually used in the matching process, increasing saturation and normalizing the gain to check the color difference between plate and CG.





Extra, about Cats…

Everyone in the industry today knows Cats as the worst movie project of the decade. When the first trailer came out the uncanny valley hit the spectators who react very badly to the view of the human live-action character’s face on a humanoid CG cat. Unfortunately, the concept is something that cannot be solved with a technical or artistic solution in the VFX final stage. So this inconvenient delayed only the inevitable, putting more press on the artists to deliver a better shot in a faster time.

But for me and some of my friends there, was one of the most formative experiences. Imagine a room with 100 artists and technicians trying to solve an unsolvable problem every day. Unsolvable because “or time or quality”, some of them super able in programming trying to code automated process to short timing. Others like Me and Andrea simple gizmo like Cat_Checker and other Python scripts to auto-populate a new nukescript with the cats templates divided by character’s name. A repetitive process for each script solved in a click. There was even a cat template  “Cat Gerardo”, if you click you will have a low-res cat with my face, hyper cringe XD.

We were working in the same room as the “1917” team, they won the VFX Oscar, we won the “Razzie Award” but much or less we had the same amount of problems to solve every day. During the super crunch delivery day, I hit my record: 23 hours working in a raw!

Disclaimer: No artist has been mistreated. The production asked kindly if we wanted to continue and most of them went out normal time. To be honest I didn’t keep pushing for a sense of duty but because was funny. Deprive yourself of sleep until you feel drunk, if you are with good company you will always remember with a smile on face :)