Rooms

Rooms are spatial elements that represent enclosed areas in a Revit model. They carry area, level, number, and name data, and are commonly used for space validation rules.

---

The Room object

{
  "id": 312045,
  "type": "Room",
  "name": "Office",
  "parent": null,
  "values": {
    "number": "1.01",
    "level": "01 eerste verdieping",
    "area": 24.5
  }
}

Key fields:

Field	Description
values.number	Room number — used for identification and uniqueness checks
name	Room name — the display name
values.level	Level name as a string
values.area	Calculated area

---

Basic filter

$[type = "Room"].{
  "id": id,
  "type": type,
  "name": name,
  "number": values.number,
  "level": values.level
}

---

Detecting duplicate room numbers

A common rule checks that no two rooms share the same number. This requires comparing each room against the rest of the dataset.

(
  $rooms := $[type = "Room"];

  $countDuplicates := function($number, $id) {
    $count($rooms[values.number = $number and id != $id])
  };

  $rooms.{
    "id": id,
    "type": type,
    "name": name,
    "number": values.number,
    "duplicateCount": $countDuplicates(values.number, id)
  }
)

Each room gets a duplicateCount field. The validator then checks that duplicateCount = 0.

Note: this pattern uses a function that queries the full $rooms array from its outer scope. The function variable captures $rooms at definition time.

---

Checking room number prefix against level prefix

A rule can verify that a room number starts with the correct prefix for its level — for example, room 1.01 should be on a level whose name starts with 1.

$[type = "Room"].(
  $roomPrefix  := $split(values.number, ".")[0];
  $levelPrefix := $split(values.level, " ")[0];

  {
    "id": id,
    "name": name,
    "number": values.number,
    "level": values.level,
    "prefixMatch": $roomPrefix = $levelPrefix
  }
)

The validator then checks prefixMatch = true.

---

Common mistakes

• Filtering type = "FamilyInstance" instead of type = "Room" — Rooms are their own object type
• Using name for uniqueness instead of values.number — names can be duplicated intentionally
• Expecting values.level to be a level id — it is a string (the level name)