IfcCurveStyle
Definition
from ISO/CD 10303-46:1992: A curve style specifies
the visual appearance of curves.
Definition from IAI: 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, i.e. 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.
NOTE
global units are defined at the single IfcProject
instance, given by UnitsInContext:IfcUnitAssignment,
the same
units are used for the geometric representation items and for the style
definitions.
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.
NOTE
the target plot scale is given by IfcGeometricRepresentationSubContext.TargetScale.
An IfcCurveStyle can be
assigned to IfcGeometricRepresentationItem's
via the IfcPresentationStyleAssignment
through an intermediate IfcStyledItem
or IfcAnnotationCurveOccurrence.
NOTE
Corresponding
STEP name:
curve_style. Please refer to ISO/IS 10303-46:1994 for the final
definition of the formal standard.
HISTORY
New entity in
Release IFC2x Edition 2.
EXPRESS specification:
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| WR11
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(NOT(EXISTS(CurveWidth))) OR
('IFCMEASURERESOURCE.IFCPOSITIVELENGTHMEASURE' IN TYPEOF(CurveWidth)) OR
(('IFCMEASURERESOURCE.IFCDESCRIPTIVEMEASURE' IN TYPEOF(CurveWidth)) AND
(CurveWidth = 'by layer'));
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Attribute definitions:
| CurveFont
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A curve style font which is used to present a curve. It can either be a predefined curve font, or an
explicitly defined curve font. Both may be scaled. If not given, then the curve font should be taken
from the layer assignment with style, if that is not given either, then the default curve font applies.
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| CurveWidth
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A positive length measure in units of the presentation area for the width of a presented curve. If not
given, then the style should be taken from the layer assignment with style, if that is not given either,
then the default style applies.
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| CurveColour
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The colour of the visible part of the curve. If not given, then the colour should be taken from the layer
assignment with style, if that is not given either, then the default colour applies.
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Formal Propositions:
| WR11
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The curve width, if provided, shall be given by an IfcPositiveLengthMeasure representing the curve width in the default measure unit, or by an IfcDescriptiveMeasure with the value 'by layer' representing the curve width by the default curve width at the associated layer.
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Inheritance graph