IFC 4.3.x development

8.15.3.15 IfcOpenCrossProfileDef

Change log

IFC4X3_RC3

added

8.15.3.15.1 Semantic definitions at the entity

A two-dimensional open profile defined by widths and slopes for the use within the swept surface geometry, in SectionedSurface in particular. The underlying coordinate system is defined by the swept surface that uses the profile definition; when used in SectionedSurface it is the XY plane of each list member of SectionedSurface.CrossSectionPositions where the profile X axis is oriented perpendicularly to the left of the Directrix (same direction as positive LateralOffset at IfcPointByDistanceExpression) as facing forward along the directrix, and the profile Y axis is oriented upwards or vertically perpendicular to the Directrix depending on the usage in the SectionedSurface. The behaviour of OpenCrossProfileDef in sweeping operation can be controlled by attribute Tags. Tags allow two consecutive cross sections to have different number of break points: points with the same tag value are connected either by assuming linear longitudinal breakline between them, or by a guide curve identified by the same Tag value as the cross section points. **Formal propositions:* The profile type shall be CURVE. * The list of slopes and the list of widths shall be of the same size, and the list of tags shall have one more member.

"open cross profile"

8.15.3.15.1 Attributes

# Attribute Type Description
IfcProfileDef
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
IfcOpenCrossProfileDef
3 HorizontalWidths IfcBoolean Indicates if the widths shall be measured horizontally or along the slopes.
4 Widths LIST [1:?] OF IfcNonNegativeLengthMeasure The horizontal widths (when HorizontalWidths=.T.) or distances along the Slope (when HorizontalWidths=.F.) for the segments in the profile. And if Horizontal=.T. the Slopes shall not be = +/- 90 deg.
5 Slopes LIST [1:?] OF IfcPlaneAngleMeasure The slope measure.
6 Tags OPTIONAL LIST [2:?] OF IfcLabel

8.15.3.15.2 Entity inheritance

dot_inheritance IfcOpenCrossProfileDef IfcOpenCrossProfileDef IfcProfileDef IfcProfileDef IfcOpenCrossProfileDef->IfcProfileDef IfcProfileDef_children 5 more... IfcProfileDef_children->IfcProfileDef

8.15.3.15.3 Definitions applying to General Usage

8.15.3.15.3.1 Property Sets for Objects

PsetName
'Pset_ProfileMechanical'

8.15.3.15.4 Formal representations

ENTITY IfcOpenCrossProfileDef
 SUBTYPE OF (IfcProfileDef);
	HorizontalWidths : IfcBoolean;
	Widths : LIST [1:?] OF IfcNonNegativeLengthMeasure;
	Slopes : LIST [1:?] OF IfcPlaneAngleMeasure;
	Tags : OPTIONAL LIST [2:?] OF IfcLabel;
 WHERE
	CorrectProfileType : SELF\IfcProfileDef.ProfileType = IfcProfileTypeEnum.CURVE;
	CorrespondingSlopeWidths : SIZEOF(Slopes) = SIZEOF(Widths);
	CorrespondingTags : (NOT EXISTS (Tags)) OR (SIZEOF(Tags) = (SIZEOF(Slopes) + 1));
END_ENTITY;