# hbmspace:celestial_relief

Terrain offset, factor and cave bounds from celestial biomes.

Each 4×4 column blends the relief heights of the surrounding 5×5 biome cells, defined in code, with a depth noise. The four outputs give the terrain zero-crossing, its vertical factor, and the bounds of noise caves.

## Fields

| Field | Meaning and default |
| - | - |
| `type` | `hbmspace:celestial_relief`. |
| `biome` | Density function yielding a celestial biome ID, such as a constant or `celestial_biomes` with `terrain: true`. An unknown ID raises an error. |
| `output` | `offset`: zero-crossing height / 128. `factor`: terrain steepness factor. `cave_ceiling`: block Y below which noise caves fade in. `cave_guard`: density at which the fade ends. |

## Example

From `data/hbmspace/worldgen/noise_settings/duna.json`:

```json
{
  "type": "hbmspace:celestial_relief",
  "biome": {
    "type": "hbmspace:celestial_biomes",
    "layers": "hbmspace:duna",
    "terrain": true
  },
  "output": "offset"
}
```