> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bedrock.cv/llms.txt
> Use this file to discover all available pages before exploring further.

# Features

> Detected entities within blocks.

A Feature is a detected entity within a [Block](/guides/concepts/blocks) — a room polygon, a door symbol, a wall segment, a dimension annotation. Features are the leaf nodes of the Drawing Index.

## Feature nesting

Features nest via `parent_feature_id` to represent containment. A receptacle is **in** a room. A room is **in** a plan block:

```
Plan Block
├── room "201"
│   ├── duplex_receptacle
│   ├── switch
│   └── smoke_detector
├── room "202"
│   └── gfci_receptacle
├── door "104"
└── wall
```

`parent_feature_id` encodes **containment only**. All other relationships (references, adjacency, scheduling) go through [Relations](/guides/concepts/relations).

## Type vocabulary

`type` is a free string — the vocabulary of construction entities is too large for an enum. Common types: `room`, `door`, `wall`, `window`, `duplex_receptacle`, `gfci_receptacle`, `smoke_detector`, `dimension`, `detail_callout`, `keynote`, `duct`, `pipe`, `beam`, `column`.

## Bounds geometry

The `bounds` field stores geometry within the parent block:

| Geometry   | Used for                  | Shape                        |
| ---------- | ------------------------- | ---------------------------- |
| `bbox`     | Symbols, equipment, doors | Axis-aligned bounding box    |
| `polygon`  | Rooms, areas              | Closed polygon with vertices |
| `polyline` | Walls, ducts, pipes       | Open line with vertices      |

All coordinates are normalized (0-1000) within the parent block's image.

## Feature metadata

The `metadata` JSON field carries domain-specific properties:

| Key           | Used on                 | Example                |
| ------------- | ----------------------- | ---------------------- |
| `fire_rating` | Walls, doors            | `2-hr`, `45-min`       |
| `elevation`   | Beams, ducts, equipment | `112'-6`               |
| `material`    | Walls, doors            | `HM`, `WD`, `concrete` |
| `size`        | Ducts, pipes            | `24x12`, `4`           |
| `designation` | Structural members      | `W16x40`               |
| `system`      | MEP elements            | `CHW`, `SAN`, `SD`     |