Supervisors Speak- Snow Mission Sequence
The Snow Mission sequence starts with Pathaan chasing after Jim for the raktbeej virus- loaded orbs that could destroy the world. The chase begins through snow clad mountains, continues on a frozen lake, eventually leading to Rubai falling into the ice & Pathaan having to decide between chasing Jim or saving Rubai’s life.
We’ll be discussing this sequence, spanning over 350 shots with our CG Supervisors, Gaurav and Debjeet.
What were the biggest creative and technical challenges you faced in this sequence? How did you overcome them?
Originally, the idea was to go with a few master setups and use them to maintain the continuity, but we ended up tweaking almost all the shots for various reasons such as the scale, volume or difference in frame rates, etc. A lot of CG elements had to be art directed to match the live shoot actions, like a ramp forming due to the explosion to enable the bike to jump off of it, or a slab on which the actor trips over and slides into the water.
This particular sequence was shot in Baikal Lake, Russia. The reason this location was picked was that it normally has very beautiful, clear, blue ice. Unfortunately the weather and light conditions weren’t cooperative when we actually shot there! So, per the Director’s vision, we started figuring out the most efficient way of replacing the ice surface with blue CGI ice for over 150shots. The idea of designing master shots didn’t work for the ice replacement because each shot was different, in terms of the angles, dynamics and camera movement. Due to this we ended up art directing each and every shot. The biggest creative challenge we faced was with the ice fissures and the cracks within them, their patterns and the formations as per the real references we got from the actual location. Our approach to the ice surface needed to be organic and procedural because we needed to be able to art direct the cracks underneath the main surface and the top layer too.
As it was not practical to go through the process of rigging, sculpting, texturing & lookdev-ing each shot, we decided to use the Houdini RBD crack system where the layout & environment would build the continuity of the cracks in the lake almost on a shot-by-shot basis.
Most of the atmospheric snow and ice kick-ups from the bike tyres were simulated in Houdini and also augmented with 2D elements to make them sit realistically in the blue CGI transparent ice.
Rotoscopy became a major part of this sequence. 80% of the sequence consisted of the actors riding the bikes, and the environment around them had to be replaced in CGI. Hence everything needed to be pulled out from the live shoot including the white snow patches to mix with the CGI ice.
In this sequence, you had to replace the bikes. Could you take us through the process?
While shooting, the stunt team used snowmobiles (on the ice) and dirt bikes (on the snow) on-location and in the studio. The bikes were LIDAR scanned for the exact dimensions as we had to match-move the bikes and replace the skis with the bike wheels, and tyres with spikes. Generic snow and ice kickups were not an option as the light conditions varied shot by shot as also the speed of the bikes, so we ended up adding the snow and ice kick-ups in almost 150 shots. Creating the illusion of the bike speed and shots ranging from real time to hi-speed, added more complexities.
How did your team pull off the underwater sequence?
Creating the whole underwater environment was challenging but fun. Floating ice pieces, underwater debris, bubbles to integrate the actors in the environment and the light interactions had to be perfect to give an underwater feel and the depth. Actors were match-moved pixel by pixel for the hair simulations and bubble generation.
What was your favourite shot to work on? And why?
Our favourite shot was when John Abraham’s bike lands on the ice surface and the interactive cracks happen on the surface. Again, we mixed the crack with Houdini RBD simulations and 2D elements. We worked on this shot as a master look shot for atleast a month, after a lot of R&D!
How long did it take for your team to complete the entire Snow Mission sequence and how many artists worked on it?
We had a team of approximately 32 Artists, at its peak, working on this sequence. The concept & asset build took approximately 12weeks and the shot finalization was another 16 weeks once we had locked the look and feel of the bigger shots. There would have been an additional 30 artists to execute the rotoscopy.