It took us a few months. Marc drew concepts, and then Baptiste tried to find in both Houdini and Nuke a look that we would like. It took a few tries, but we were super happy with how it turned out. We wanted to avoid the 80s predator invisibility look; we wanted to have something a bit more magical and less sci-fi.
"In the end, Baptiste made an effect that was mostly made in comp (we only generated a few simple masks in 3D), allowing us to render and iterate quickly on the look for each shot.