Skin that isn't plastic

The younger Ioma came into the game looking like a figurine: a hard sheet of highlight down her cheek and hand, the same sheen on her coat. Here is the same frame, brightened the same amount, before and after.

What was actually wrong

Rather than nudge sliders, we measured. Every generated character comes in through Unreal's glTF import with one material for the whole body, and three things were stacking up:

• Specular at twice a dielectric. The import's default material feeds Unreal's specular pin 1.0. Skin is about 0.35 on that scale, linen a little less.
• Glossy skin in the roughness map. Hunyuan paints roughness per pixel, and on her face and hands it sits between 0.2 and 0.5, against 0.88 on the cloth. Under a low sun that is a wet-plastic highlight.
• Metal where there is none. The metallic channel is a low noise everywhere, about 9%, which greys the diffuse and adds a second sheen.
• No scatter. Skin passes light under its surface; a plain lit surface doesn't, and the eye knows.

What we did

The ride's build script now makes her a material of its own instead of keeping the import's, and the skin mask the character generator already writes (head, neck, hands and forearms, by the rig's weights and the albedo's colour) tells it where skin is:

• metallic 0, specular 0.3 on cloth and 0.35 on skin
• skin roughness remapped into a matte band and broken up with fine noise so the highlight never sits as one sheet; cloth never shinier than linen
• Hunyuan's normal map kept
• the Subsurface shading model on the skin only: her own colour pushed red, scattered a little; none on the cloth

Every number is a parameter on the material, so the look can be tuned from shots rather than by rebuilding. The same function will serve the mother, the Wellwright and whoever comes next: it needs only the rig folder and its mask.

One more thing from the same session: the chase camera started taking the mouse the instant control was released, while the letterbox was still opening. It waits for the bars now.