# hbmspace:noise_caves

Noise caves replacing the aquifer.

Put the function inline as `noise_router.final_density` of the noise settings with no `aquifers` object; a reference to a density-function file there is ignored. A cell with positive density is solid; otherwise it is air where `caves` is negative, including below sea level, and the level's fluid elsewhere.

## Fields

| Field | Meaning and default |
| - | - |
| `type` | `hbmspace:noise_caves`. |
| `terrain` | The level's final density. |
| `caves` | Density function; negative values are caves. |

## Example

Abridged, from `data/hbmspace/worldgen/noise_settings/mun.json`:

```json
{"type": "hbmspace:noise_caves", "caves": "…", "terrain": "…"}
```