IFC 4.3.x development

8.8.3.6 IfcBoundingBox

8.8.3.6.1 Semantic definitions at the entity

The IfcBoundingBox defines an orthogonal box oriented parallel to the axes of the object coordinate system in which it is defined. It is defined by a Corner being a three-dimensional Cartesian point and three length measures defining the X, Y and Z parameters of the box in the direction of the positive axes.

NOTE  Any subtype of IfcProduct having a product shape representation may have a bounding box representation. The 'Box' representation identifier defined at IfcShapeRepresentation utilizes the IfcBoundingBox as the simpliest 3D shape representation.

half space solid

As shown in Figure 1, the IfcBoundingBox is defined with its own location which can be used to place the IfcBoundingBox relative to the geometric coordinate system. The IfcBoundingBox is defined by the lower left corner (Corner) and the upper right corner (XDim, YDim, ZDim measured within the parent co-ordinate system).

Figure 1 — Bounding box

 

NOTE  Corresponding STEP type box_domain defined in ISO 10303-42.

HISTORY  New entity in IFC1.0.

8.8.3.6.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

> IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcBoundingBox
1 Corner IfcCartesianPoint Location of the bottom left corner (having the minimum values).
2 XDim IfcPositiveLengthMeasure Length attribute (measured along the edge parallel to the X Axis)
3 YDim IfcPositiveLengthMeasure Width attribute (measured along the edge parallel to the Y Axis)
4 ZDim IfcPositiveLengthMeasure Height attribute (measured along the edge parallel to the Z Axis).
Dim INVALID The space dimensionality of this class, it is always 3.

8.8.3.6.2 Entity inheritance

dot_inheritance IfcBoundingBox IfcBoundingBox IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcBoundingBox->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.8.3.6.3 Formal representations

ENTITY IfcBoundingBox
 SUBTYPE OF (IfcGeometricRepresentationItem);
	Corner : IfcCartesianPoint;
	XDim : IfcPositiveLengthMeasure;
	YDim : IfcPositiveLengthMeasure;
	ZDim : IfcPositiveLengthMeasure;
 DERIVE
	 Dim : IfcDimensionCount := 3;
END_ENTITY;