The Portable
Door

One of the more genuinely unusual briefs we've had: create a head of hair that behaves like hair — moves like hair, sits like hair — but periodically arranges itself to spell the word "beware." It needed to feel organic, not mechanical. The kind of thing that reads as strange before the audience can quite articulate why.

The effect was built entirely in Houdini. We started with HairGen, using guide curves to define the base movement and direction of each strand — essentially building a skeleton for the sim before any dynamics entered the picture. Those prototype animated hairs were then fed into Vellum, Houdini's constraint-based solver, which handled the per-strand physics: how the hair responds to gravity, momentum, and the character's own movement. Vellum runs each strand as a series of constraints rather than a rigid chain, which gives you that subtle, unpredictable quality that makes hair look real rather than simulated.

Once the sim was locked, the strands were point-deformed back onto the original guide curves — keeping the performance intact while layering the physical behaviour on top. The final renders went to compositing to be integrated back into the plate, matching the on-set lighting and blending seamlessly with the practical hair elements already captured in camera.

Christoph Waltz plays two characters in the film, both of whom wield magic — which meant designing a visual language for how that magic looks and moves. The brief was energy: something between electricity and light, with an internal logic that felt deliberate rather than arbitrary.

The beam effects were built using a combination of POP and Pyro simulations in Houdini. The path of each beam was established by drawing a curve between two points in the scene — giving us spatial control over the trajectory before any simulation ran. Custom noise was then applied along the curve to break up the line and give it that unstable, charged quality. From there, a scattered particle simulator emitted moving points along the curve's path, producing the pulsing, lightning-like energy effect visible in the final shots. The result reads less like a light beam and more like something barely contained.

Effects that wrap around or flow across a character's body — energy bleeding into clothing, sparks tracing across skin — were built using the same approach on a much finer scale, with the curve geometry fitted to the actor's form and the noise dialled back to keep the detail subtle.

The beam toolkit turned out to be unusually flexible. For a scene featuring a magical glowing blue orb — a modern take on the crystal ball — we combined the particle techniques with a spherical mesh as a containment volume, letting the particle energy circulate within the orb's surface rather than travel along a path. It gave the orb that sense of something alive inside it.

Beyond the hero effects, the scope of work across the film was broad: magical doorways with animated thresholds, tractor beam sequences, holographic UI elements, and full-on orb battles between characters.

On the creature side, we handled CGI extensions for an oversized ear gag — building and integrating a photo-real flesh prosthetic that had to hold up in close-up. Each of these required its own approach, but the common thread was finding the simplest technical path to the most convincing result.

"The Portable Door had such a variety of magic effects — animated hair, giant ears, magical doorways, tractor beams, holograms and orb battles. The project really challenged us technically and creatively." — Lindsay Adams, VFX Supervisor