Watercolor

This piece explores how 3D geometry and velocity data can drive painterly watercolor motion inside Houdini’s Copernicus framework. Instead of relying on traditional rendering or compositing tricks, the visual language emerges from solver logic — transforming motion into fluid ink diffusion

Download the Watercolor Effect Solver HIP file if you want to dissect the solver and push the watercolor system yourself.

The project focuses on translating physical movement into organic pigment behavior. Velocity fields are extracted from animated geometry and fed into a custom solver that simulates bleed, spread, and soft edge breakup associated with watercolor media. The result is a hybrid aesthetic: procedural at its core, but expressive and tactile in feel.

This study serves as both a technical experiment and a visual research piece, pushing non-photoreal 3D workflows toward illustration-driven motion design. No external renderers were used; the entire look is generated natively within Houdini.

Achieving organic fluid motion that carries naturally across frames.

• Designing a believable watercolor-style outline that reads as hand-drawn.
• Rasterizing velocity attributes to drive RGB smearing in a controllable, art-directable way.
• Balancing solver diffusion so motion feels painterly while preserving form readability.
• Preventing temporal artifacts and breakup during fast motion transitions.

A custom Copernicus solver converts geometry-derived velocity fields into a raster diffusion system that advects RGB data to simulate watercolor pigment flow.

Edge detection and outline synthesis are integrated into the solver pipeline to preserve structural readability while maintaining painterly breakup.

Attribute rasterization bridges 3D motion and 2D pigment behavior, enabling art-directable control over smear intensity, diffusion rate, and temporal coherence.

Animate base geometry and extract velocity attributes as the motion driver. Rasterize attributes into a Copernicus solver to advect and diffuse color. Iterate solver controls to shape outlines, smear behavior, and frame-to-frame flow.

Explore integration of background imagery to expand compositional depth

Introduce ground collisions to anchor pigment motion in physical space

Develop additional controls for foreground/background balance to improve readability

The watercolor motion isn’t a texture effect — it’s literally pixels being pushed around by simulated velocity, so every smear is driven by real motion data rather than a painted overlay.

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A post shared by Ronald Fong • 3D Motion Designer • Educator (@ronald_fong)

Design & Direction: Ronald Fong