# `GeometryData.index`

> 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 [`GeometryData`](GeometryData.md) · labs, `@experimental` · since 2.0.0

```ts
readonly index?: Uint32Array;
```

Three per triangle.

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `index` names no product |
| 2. A precedent | pass: [Unity Mesh.vertices](https://docs.unity3d.com/ScriptReference/Mesh-vertices.html) (row `G9`); [Unity Mesh.GetIndices](https://docs.unity3d.com/ScriptReference/Mesh.GetIndices.html) (row `G9`); [glTF 2.0 mesh primitives (indices)](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#meshes) (row `K4`); [Unity Mesh](https://docs.unity3d.com/ScriptReference/Mesh.html) (row `K4`) |
| 3. Two apps, or labs | labs (`@experimental` at a stable path, reached through `has()` or `supports()`): it graduates when a second app uses it; apps today: app-378d190f1b, app-bcb7ef21da, app-f9a32142f1, app-fc306ec3dc |
| 4. The cheaper fix first | decided per need in Appendix B: rows `G9`, `K4` at tier labs, stable (a member only where no rule, data, asset or app code serves the need) |