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The Boy and The Octopus: CFX Workflows
Untold Studios CFX Supervisor and Head of VFX explain Houdini solutions for simulating octopus tentacles, skin, and hair in Disney's 2024 holiday short, covering challenging creature CFX.
Abstract
Aman Akram (CTO) and Andrea Lacedelli (CFX Supervisor) of Untold Studios present the Houdini CFX workflows for Disney's short The Boy and the Octopus, covering tentacle, skin, and hair simulation under a tight six-month, non-destructive procedural pipeline. The octopus is built as a non-hollow tetrahedral mesh simulated with tet stretch constraints, driven from the inside by a stripped-down tissue-inspired core using metaballs and magnets to push volume, with procedural groups exposed as artist sliders for stiffness and a sucker-attraction system gluing tentacles to the boy's head. They detail a thin double-sided clear-coat wetness layer created via Zbrush displacement, ray-casting and VDB operations and stabilized with a pinned cloth simulation around the eye socket, plus five long-hair grooms simulated with Vellum hair constraints, glues, and touch constraints, and a Mickey hat solved as a cloth sim with stitch and shape-match constraints. Rendering is done in Arnold with grooms, feathers, and hair deformed at render time in C++ to keep the data footprint low and time-to-first-pixel fast on their cloud-based pipeline.
How to read this
- Category
- Production talk: creature CFX breakdown
- Contributions
- Demonstrates Houdini CFX for an octopus: a non-hollow tetrahedral mesh with tet stretch constraints driven by a stripped-down tissue-inspired core using metaballs and magnets, plus artist sliders and a sucker-attraction glue system
- Shows a thin double-sided clear-coat wetness layer from Zbrush displacement, ray-casting and VDB ops, stabilized by a pinned cloth sim around the eye socket
- Covers five Vellum long-hair grooms with glue and touch constraints, a shape-matched cloth Mickey hat, and Arnold rendering with render-time C++ groom deformation for low data footprint
- Context
- Untold Studios' CFX workflow for Disney's short The Boy and the Octopus, applying Houdini Vellum and tetrahedral solvers in a non-destructive procedural pipeline.
- Correctness
- Studio practice, not peer-reviewed; results are production-proven and shaped by a tight six-month, cloud-pipeline schedule, so techniques are pragmatic choices rather than generalized methods.
- Clarity
- Accessible breakdown for Houdini-literate viewers; one viewing conveys the setups and artist-control philosophy.
- How to read it
- Watch for the tet-core-plus-magnets volume-driving approach and the render-time deformation trick; revisit specific segments (tentacle core, wetness layer, hair) if you build comparable creature CFX.
Related work
- Simulating the Perfect Groom for a Bovine Biker | Untold Studios | FMX HIVE 2023 2023 / FMX
- Creating a Photorealistic Hyena 2022 / FMX
- Creatures in Houdini | Ahmed Gharraph | FMX 2019 2019 / FMX
- Feathers: From Model to Groom to Render | nineteentwenty | Character FX & Crowds Production Talks 2019 / Houdini
Keywords
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