Rachael's tragic reappearance in Blade Runner 2049 is the latest high-profile 'digital double', bringing a CG-enhanced version of an actor from a previous film into a modern production – following Rogue One's recreation of the deceased Peter Cushing and a younger version of the then-still-alive Carrie Fisher.
The modern, re-created Rachael materialises on-screen due to a stuntwoman's performance on set, a 3D capture of the head of actress Sean Young (who played the character in the 1982 original) and some painstaking modelling, texturing and animation by VFX house MPC.
Read on to see how MPC created the digital double of Rachel for Blade Runner 2049, and check out its VFX breakdown reel above.
MPC's first step was scanning Sean's head. While the actress had obviously aged in the 35 years between the films, bone structures don't change much over time.
This gave MPC's modellers an accurate skull to work from, calculating proportions such as the bridge of nose, cheekbones and jaw line.
When sculpting and texturing the head, the modellers and artists worked from reference frames from the original Blade Runner. This proved to be tricky and require a lot of artistic licence, as the character usually appeared in dark scenes and soft focus due to a shallow depth-of-field.
To test the model, MPC recreated three scenes from the original Blade Runner, with the digital double inserted. These were shown – alongside clips from the original film – to the sequel's filmmakers in what was essentially a game of spot-the-digital-double. The double passed.
On set, a body double acted out the scenes with Harrison Ford, Jared Leto and Sylvia Hoeks – with multiple cameras capturing the footage (and lighting) from as wide range of angles. The stuntwomen and Sean Young also reenacted each scene, with 3D data captured using Dimensional Imaging's DI4D capture rig and a FACS capture kit for facial poses and expressions.
The new Rachael was hand-animated using the on-set motion-captured data as reference. MPC says that this was to give the animators more flexibility and the director more control – with each detail from her mouth shape to the number of folds in her eyelid matched against footage of the actress.