Create Dimensions - Rooms

In this post, we discussed creating dimensions with the Revit API. But we only discussed dimensioning walls. Sometimes, however, we want to dimensions to include other elements - balconies, for instance, which are not typically drawn with wall elements.

In this case, we can use our room separation lines.

    def r2(num):
    return round(num, 2)
 
    doc = DocumentManager.Instance.CurrentDBDocument
    rooms = FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Rooms).WhereElementIsNotElementType().ToElements()

Once that's done, we can iterate through all these lines to find their maximum extents (for the purposes of this post, I'll assume we just want to dimension the rooms' x extents).

    leftmost_x = float('inf')
    rightmost_x = 0
    line_left = None
    line_right = None
 
    for line in roomlines:
        info = line.Location.Curve
        direction = info.Direction
        origin = info.Origin
        if r2(direction.X) == 0: #We only want vertical lines here
            if origin.X < leftmost_x:
                leftmost_x = origin.X
                line_left = line 
            if origin.X > rightmost_x:
                rightmost_x = origin.X
                line_right = line 

The rest of the process is identical to the one we used to dimension walls. We need to create a line and a reference array, then pass these items to Create.NewDimension()

    #Create line for dimension
    top_point = 0
    for line in roomlines:
        info = line.Location.Curve
        direction = info.Direction
        origin = info.Origin
        if r2(direction.Y) == 0: #We only want horizontal lines now
            if origin.Y > top_point:
                top_point = origin.Y 
    dimension_y = top_point + 1 #Add a foot to ensure we're far enough away
    dimension_left_point = XYZ(leftmost_x, dimension_y, 0)
    dimension_right_point = XYZ(rightmost_x, dimension_y, 0)
    dimension_line = Line.CreateBound(dimension_left_point, dimension_right_point)
 
    #Create reference array
    reference_left = line_left.GeometryCurve.Reference
    reference_right = line_right.GeometryCurve.Reference
    refArray = ReferenceArray()
    refArray.Append(reference_left) #Note that "Append" is spelt with a capital A here!
    refArray.Append(reference_right)
 
    #Create dimension
    TransactionManager.Instance.EnsureInTransaction(doc)
    new_dim = doc.Create.NewDimension(doc.ActiveView, dimension_line, refArray)
    TransactionManager.Instance.TransactionTaskDone()

This code above can of course be combined with a wall-dimensioning script to allow for a mix of wall and room-separation-line dimensioning.