Star of the new series, Jodie Whittaker, is at the center of the action, as stained glass explodes around her. Director Jamie Childs shot the actress against greenscreen at Cardiff's BBC Studios, with Watts in attendance to supervise.
Watts was involved heavily in the creative from the outset and led the vision to deliver on the initial brief. His artistic control defined the direction the film took, especially the focus on the glass with slow-motion burst.
The look and detail of the structure of the splintering dome, based on the Pantheon in Rome, was built entirely in CG by the Freefolk team. Their VFX included simulations consisting of glass effects, the stained-glass color, domed glass ceiling and detailed reflections of Jodie Whittaker in the emanating shards of glass.
According to Harin Hirani, CG supervisor, the artists used the fracturing tools within SideFX’s Houdini to break the glass and simulate it falling, and then exported this to Autodesk’s Maya for rendering. To add more drama to the impact, they created a pulsing ripple through the geometry using deformers and added a secondary layer of smaller glass fragments to add more interest and detail to the falling pieces. This all then needed to be time warped accordingly to work with the dynamic speed changing that happens throughout the shot.
CG artist Alaric Holberton says the first thing he wanted to do before even getting started on the shatter was a shockwave running through the glass and frame. “Clearly the helicopter crash scene in The Matrix had left a lasting impression on me, and it was great to see in a ‘The Slo Mo Guys’ video where they throw a hammer through a mirror that this does to a certain degree actually happen,” he says.
For the main shatter, everything starts at the center of the ceiling and radiates outwards. “If I had used the actual distance from the center, the shockwave would have spread out at inconsistent speeds due to the shape of the ceiling, so instead I used the UV position of the glass (which had been UV’d evenly),” he explains. “I temporarily transferred the UVs and normals from the glass to the frame so they could both be displaced along those normals depending on time and UV distance from the center.”
All this work was done in Houdini.
For the shattering, Holberton used the classic Voronoi fracturing. “With Houdini’s relatively recent rock-solid Booleans, cutting up geometry with shapes has become a popular method for achieving a different look in fracturing. However, I felt for glass, Voronoi gives a good look. I did the fracturing within a foreach (pane of glass) loop so the fracture lines didn’t cross over from one pane of glass to the next, as that wouldn’t happen in the real world. In scattering the points for the fracture, I was sure to turn off Relax Iterations so there’s no attempt to spread out the points evenly, which would result in more uniform-sized shards of glass. Even so, it does result in relatively similar-sized pieces, so after the initial fracture, I had a proportion of those pieces fractured again, resulting in a wide range of sizes.”
Of course, everyone knows when they drop a glass, not only do you have the main pieces to pick up, but there are also hundreds of tiny pieces to wipe up. For this, Hoberton had the edges of the glass where it breaks emit thousands of particles, then instanced tiny pieces of glass onto them. While not strictly volume conserving of the original glass, trying to facture the glass to that degree would be impractical and visually is indiscernible, he notes.
For the dynamics themselves, Hobertson applied an initial force in the direction of the normal and added a random rotation so everything moves off with bang instead of just leaving it gravity. “I also applied an outward force for those pieces in the center, as we wouldn’t want the Doctor being showered in glass. Once the pieces get below waist height, I simply switched their dynamics off as an optimization and to prevent them crashing back into frame. Once I was happy with the simulation I cached it to disk and time warped as needed,” he says.
The final ingredient was taking part of that cache, duplicating it and moving it in front of camera to keep the Doctor more obscured than the original amount of glass would allow.
The impressive film was turned around in just one month in time for Doctor Who fans to enjoy in the run up to the program’s return on October 7.
The trailer, graded by Holly Greig, with Cheryl Payne as VFX producer and Harin Hirani as CG Supervisor, can be viewed at: https://freefolk.com/work/doctor-who-trailer/.