> ## 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` |


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