The bounding box is an invisible 3D rectangular space that contains all model elements, annotation elements, and datum elements defined in a family-based element.
Datum extents are the exception. For example, a horizontal reference plane will only affect a top or bottom of the bounding box, not either of its sides. The bounding box is oriented with respect to the family definition.
Bounding boxes of columns represented in orange
The top, bottom, and sides of the bounding box rotate accordingly to maintain its relationship with the element as it rotates.
Bounding boxes rotating with elements
General purposes of the bounding box
- If a family does not have a family origin explicitly defined, the origin will default to the center of the bounding box. This origin affects placement of instances and their behavior when the instance type or family is changed.
- The bounding box helps define the joining and cutback of structural framing elements.
Curved Beams
Curved beams present a unique instance of the bounding box. The bounding box bends to meet the needs of the beam. This provides accurate joining and cutback with the beam.
