Features

A Feature is a detected entity within a Block — 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.

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`

Getting Started

Core Concepts

Account

Resources

Feature nesting

Type vocabulary

Bounds geometry

Feature metadata

​Feature nesting

​Type vocabulary

​Bounds geometry

​Feature metadata

Feature nesting

Type vocabulary

Bounds geometry

Feature metadata