# `MaterialSpec.roughness`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Property of [`MaterialSpec`](MaterialSpec.md) · inherited by [`MaterialInput`](MaterialInput.md) · stable · since 2.0.0

```ts
roughness?: number;
```

0..1.

**Default:** 0.5

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `roughness` names no product |
| 2. A precedent | pass (through its owner [`MaterialSpec`](MaterialSpec.md)): [glTF 2.0 metallic-roughness material](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#metallic-roughness-material) (row `K10`); [glTF KHR_materials_sheen](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_sheen) (row `K10`); [glTF KHR_materials_transmission](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_transmission) (row `K10`); [glTF KHR_materials_unlit](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_unlit) (row `K10`) |
| 3. Two apps, or labs | pass: 28 apps (ledger: app-04c2774145, app-0c773a4ee3, app-37356bf09f, app-378d190f1b, app-4762caacdc, app-4f16d2f6da, app-4fd23bc869, app-510d750508 and 20 more; fleet cross-check: app-fc07850558) |
| 4. The cheaper fix first | decided per need in Appendix B: rows `K10` (through its owner [`MaterialSpec`](MaterialSpec.md)) at tier stable (a member only where no rule, data, asset or app code serves the need) |