IFC 4.3.x development IfcCircleHollowProfileDef Semantic definitions at the entity

IfcCircleHollowProfileDef defines a section profile that provides the defining parameters of a circular hollow section (tube) to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profile's centre of the bounding box (for symmetric profiles identical with the centre of gravity).

HISTORY  New entity in IFC2x2.

Figure 1 illustrates parameters of the circular hollow profile definition. The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of:

By using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (for example, upper-left bound). The parameterized profile is defined by a set of parameter attributes.

"CHS-shape profile" Attributes

# Attribute Type Description
1 ProfileType IfcProfileTypeEnum Defines the type of geometry into which this profile definition shall be resolved, either a curve or a surface area. In case of curve the profile should be referenced by a swept surface, in case of area the profile should be referenced by a swept area solid.
2 ProfileName OPTIONAL IfcLabel Human-readable name of the profile, for example according to a standard profile table. As noted above, machine-readable standardized profile designations should be provided in _IfcExternalReference.ItemReference_.
HasExternalReferenceSET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjectsReference to external information, e.g. library, classification, or document information, which is associated with the profile.

> IFC4 CHANGE New inverse attribute
HasProperties SET [0:?] OF IfcProfileProperties FOR ProfileDefinition Additional properties of the profile, for example mechanical properties.

> IFC4 CHANGE New inverse attribute
3 Position OPTIONAL IfcAxis2Placement2D Position coordinate system of the parameterized profile definition. If unspecified, no translation and no rotation is applied.
4 Radius IfcPositiveLengthMeasure The radius of the circle.
5 WallThickness IfcPositiveLengthMeasure Thickness of the material, it is the difference between the outer and inner radius. Entity inheritance

dot_inheritance IfcCircleHollowProfileDef IfcCircleHollowProfileDef IfcCircleProfileDef IfcCircleProfileDef IfcCircleHollowProfileDef->IfcCircleProfileDef IfcParameterizedProfileDef IfcParameterizedProfileDef IfcCircleProfileDef->IfcParameterizedProfileDef IfcParameterizedProfileDef_children 10 more... IfcParameterizedProfileDef_children->IfcParameterizedProfileDef IfcProfileDef IfcProfileDef IfcParameterizedProfileDef->IfcProfileDef IfcProfileDef_children 5 more... IfcProfileDef_children->IfcProfileDef Definitions applying to General Usage Property Sets for Objects

'Pset_ProfileMechanical' Formal representations

ENTITY IfcCircleHollowProfileDef
 SUBTYPE OF (IfcCircleProfileDef);
	WallThickness : IfcPositiveLengthMeasure;
	WR1 : WallThickness < SELF\IfcCircleProfileDef.Radius;