# Biome radiation

Direct radiation exposure by biome.

**since NTM 1.0.1**

File: `data/<namespace>/hbm/biome_radiation/<path>.json`.

This server registry loads with the world. Each rule applies direct radiation exposure to living entities in the selected biomes every tick, at one twentieth of its per-second rate. Water or rain applies `wet_multiplier`. Exposure respects [radiation immunity](https://movblock.mov/ntm-next/wiki/hazards-and-radiation.md#tags) and players' worn resistance; it does not emit into the surrounding radiation field.

Each biome belongs to one rule. Overlapping selectors fail world startup. Replace the original resource ID to change a shipped rule. Reopen singleplayer or restart the server after editing rules or their tags.

## Fields

| Field | Meaning and default | Range |
| - | - | - |
| `targets` | Biome ID, `#namespace:tag`, or biome-ID list. | |
| `rad_per_second` | Dry radiation dose in RAD/s. | `[0, f64::MAX]` |
| `wet_multiplier` (Optional) | Multiplier while in water or rain; default 1. | `[0, f64::MAX]` |

The product of `rad_per_second` and `wet_multiplier` must be finite. Shipped rules `hbm:crater_outer`, `hbm:crater`, and `hbm:crater_inner` apply 0.5, 5, and 25 RAD/s respectively, each with a wet multiplier of 5. They replace the 1.0.0 [`explosion_config`](https://movblock.mov/ntm-next/wiki/game-settings/explosion_config.md) keys `crater_biome_rad`, `crater_biome_inner_rad`, `crater_biome_outer_rad` and `crater_biome_water_mult`.

## Example:

File: `data/hbm/hbm/biome_radiation/crater_outer.json`.

```json
{"targets": "hbm:crater_outer", "rad_per_second": 0.25, "wet_multiplier": 2.0}
```