# hbm:light_blocking_height

Moves placement positions to the light-blocking terrain surface.

Replaces each position's Y coordinate with the first free height above a light-attenuating block in its X/Z column. A column with no such surface yields no position.

## Fields

| Field | Meaning and default |
| - | - |
| Additional fields | None |

## Example:

An entry in a placed feature's `placement` array:

```json
{"type": "hbm:light_blocking_height"}
```