IFC 4.3.0.1 (IFC4X3) development

8.12.3.5 IfcCurveStyle

8.12.3.5.1 Semantic definition

An IfcCurveStyle provides the style table for presentation information assigned to geometric curves. The style is defined by a color, a font and a width. The IfcCurveStyle defines curve patterns as model patterns, that is, the distance between visible and invisible segments of curve patterns are given in model space dimensions (that have to be scaled using the target plot scale).

Styles are intended to be shared by multiple IfcStyledItem's, assigning the style to occurrences of (subtypes of) IfcGeometricRepresentationItem's. Measures given to a font pattern or a curve width are given in global drawing length units.

The measure values for font pattern and curve width apply to the model space with a target plot scale provided for the correct appearance in the default plot scale.. For different scale and projection dependent curve styles a different instance of IfcCurveStyle needs to be used by IfcPresentationStyleAssignment for different IfcGeometricRepresentationSubContext dependent representations.

An IfcCurveStyle can be assigned to IfcGeometricRepresentationItem's via the IfcPresentationStyleAssignment through an intermediate IfcStyledItem or IfcAnnotationCurveOccurrence.

8.12.3.5.5 Formal representation

ENTITY IfcCurveStyle
SUBTYPE OF (IfcPresentationStyle);
CurveFont : OPTIONAL IfcCurveFontOrScaledCurveFontSelect;
CurveWidth : OPTIONAL IfcSizeSelect;
CurveColour : OPTIONAL IfcColour;
ModelOrDraughting : OPTIONAL IfcBoolean;
WHERE
IdentifiableCurveStyle : EXISTS(CurveFont) OR EXISTS(CurveWidth) OR EXISTS(CurveColour);
MeasureOfWidth : (NOT(EXISTS(CurveWidth))) OR
(CurveWidth = 'by layer'));
END_ENTITY;