Skin in the Game

Oluseyi Ekanem
Aug 17
2 min read

The Rat Trap Project – Post 6: Skin in the Game

When you build a film inside one tool, things break. When you build a film across multiple tools—things disappear, snap, or melt into chaos. That’s exactly what happened when we brought our Metahuman character, Baker, into Houdini Solaris. She arrived without skin. No eyebrows. No eyelashes. Just bare geometry. It was like directing an actor who walked on stage without makeup, costume, or even a face.

Rebuilding a Metahuman from Scratch

Metahumans look flawless in Unreal, but outside that ecosystem, you’re on your own. Solaris and MaterialX give you incredible rendering power—but they don’t hand you ready-made human skin.

So we rolled up our sleeves and rebuilt it: pulling textures from Unreal, wiring them into a new MaterialX shader, and debugging every glitch along the way.

The hardest parts?

Normal maps went wrong—until we discovered they had to be set to “raw” color space and passed through a proper normal node.
Geometry data missing—tangents and normals weren’t reaching the shader, so we manually injected them.
Material assignments wiped during FBX merge, forcing us to reconnect surfaces one by one inside the Material Library LOP.

It wasn’t glamorous—but it was the kind of “plumbing work” that keeps the pipeline flowing.

One Node at a Time

In the end, we built a custom MaterialX skin shader on top of standard_surface.

Albedo, roughness, and normals—all wired with the correct color spaces.
Geometry property value nodes feeding in the missing data.
Simplified placeholders for eyes and teeth to get clean test renders.

It’s not “final,” but it’s solid. And in indie animation, solid is gold.

Why It Matters

This isn’t just a story about skin textures. It's proof that small teams—even from the Global South—can harness high-end tools like Houdini and Unreal to shape vibrant narratives. No shortcuts. No compromises. Just vision, resilience, and technical craftsmanship.

That’s what The Rat Trap is about. That’s what we’re building at PAITAN—animation that’s ambitious, African, and unafraid to get messy in the details.

Looking Ahead: Houdini 21 and Metahumans

Everything we’ve accomplished here was done in Houdini 20.5, where getting a Metahuman to look right meant rebuilding skin materials node by node. But Houdini 21, scheduled for release at the end of August 2025, introduces a Metahuman import plugin, developed in partnership with Epic Games, that promises to significantly streamline the character import process.

This is where PAITAN shines—we’re at the forefront of cutting-edge technology, and we’ll be among the first to trial, adapt, and integrate this plug-in into our pipeline.

Less time debugging materials. More time focusing on storytelling, performance, and emotional nuance.