git:20261028.62f2e2f to git:20261031.845cf45

---

name: paint

description: Create realistic painted surfaces with Three.js TSL on WebGPU. Use for trains, vehicles, signs, buildings, machinery and architecture.

---

# Paint

Treat paint as a layered surface rather than a single colour.

## Layers

Conceptually:

substrate -> primer -> paint -> protective/clear layer -> wear/dirt

Not every object needs every layer explicitly, but the shader should model the important optical consequences.

## Controls

Consider:

- base colour

- roughness

- specular

- clearcoat

- clearcoat roughness

- fine surface normal

- colour variation

- fading

- scratches

- edge wear

- dirt

## Automotive/train paint

Painted train bodies can use a smooth coloured coating with moderate clearcoat and subtle roughness variation.

Avoid mirror-like paint unless the object is intentionally polished.

## Wear

Wear should be spatially meaningful:

- edges

- handles

- door areas

- maintenance access

- exposed lower sections

- high-contact surfaces

Scratches can expose primer or substrate where appropriate.

## Dirt

Dirt should accumulate in:

- seams

- recesses

- lower panels

- joints

- underbody areas

Do not apply uniform brown/grey noise.

## Signs

Painted signage should retain crisp lettering while allowing the sign substrate to age separately.