IfcCompositeCurveSegment

BACnet MVD

#### IfcCompositeCurveSegment

Natural language names

| Segment einer zusammengesetzten Kurve
| Composite Curve Segment
| Segment de courbe composite

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC4 Addendum 1
IfcCompositeCurveSegment |  |  |  |
SameSense |  |  | MODIFIED | Type changed from BOOLEAN to IfcBoolean.

##### Semantic definitions at the entity

Entity definition

An IfcCompositeCurveSegment is a bounded curve constructed for the sole purpose to be a segment within an IfcCompositeCurve.

> NOTE Definition according to ISO/CD 10303-42:1992
> A composite curve segment is a bounded curve together with transition information which is used to construct a composite curve.

> NOTE Entity adapted from composite_curve_segment defined in ISO 10303-42.

> HISTORY New entity in IFC1.0

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
1 | Transition | IfcTransitionCode |  | The state of transition (i.e., geometric continuity from the last point of this segment to the first point of the next segment) in a composite curve. |  | X

2

SameSense

IfcBoolean

An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If SameSense is false, the point with highest parameter value is taken as the first point of the segment.

> NOTE If the datatype of ParentCurve is IfcTrimmedCurve, the value of SameSense overrides the value of IfcTrimmedCurve.SenseAgreement

X

3 | ParentCurve | IfcCurve |  | The bounded curve which defines the geometry of the segment. |  | X
| UsingCurves | IfcCompositeCurve @Segments | S[1:?] | The set of composite curves which use this composite curve segment as a segment. This set shall not be empty. |  | X
| Dim :=ParentCurve.Dim | IfcDimensionCount |  | The space dimensionality of this class, defined by the dimensionality of the first ParentCurve. |  | X

Formal Propositions

Rule | Description
--- | ---
ParentIsBoundedCurve | The parent curve shall be a bounded curve.

##### Inherited definitions from supertypes

Entity inheritance
Attribute inheritance

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
IfcRepresentationItem

LayerAssignment

IfcPresentationLayerAssignment
@AssignedItems

S[0:1]

Assignment 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.

X

StyledByItem

IfcStyledItem
@Item

S[0:1]

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.

X

X

IfcGeometricRepresentationItem
IfcCompositeCurveSegment
1 | Transition | IfcTransitionCode |  | The state of transition (i.e., geometric continuity from the last point of this segment to the first point of the next segment) in a composite curve. |  | X

2

SameSense

IfcBoolean

An indicator of whether or not the sense of the segment agrees with, or opposes, that of the parent curve. If SameSense is false, the point with highest parameter value is taken as the first point of the segment.

> NOTE If the datatype of ParentCurve is IfcTrimmedCurve, the value of SameSense overrides the value of IfcTrimmedCurve.SenseAgreement

X

3 | ParentCurve | IfcCurve |  | The bounded curve which defines the geometry of the segment. |  | X
| UsingCurves | IfcCompositeCurve @Segments | S[1:?] | The set of composite curves which use this composite curve segment as a segment. This set shall not be empty. |  | X
| Dim :=ParentCurve.Dim | IfcDimensionCount |  | The space dimensionality of this class, defined by the dimensionality of the first ParentCurve. |  | X

##### Formal representations

XML Specification
`<xs:element name="IfcCompositeCurveSegment" type="ifc:IfcCompositeCurveSegment" substitutionGroup="ifc:IfcGeometricRepresentationItem" nillable="true"/>
<xs:complexType name="IfcCompositeCurveSegment">
<xs:complexContent>
<xs:extension base="ifc:IfcGeometricRepresentationItem">
<xs:sequence>
<xs:element name="ParentCurve" type="ifc:IfcCurve" nillable="true"/>
</xs:sequence>
<xs:attribute name="Transition" type="ifc:IfcTransitionCode" use="optional"/>
<xs:attribute name="SameSense" type="ifc:IfcBoolean" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcCompositeCurveSegment
SUPERTYPE OF(IfcReparametrisedCompositeCurveSegment)
SUBTYPE OF (IfcGeometricRepresentationItem);
Transition : IfcTransitionCode;
SameSense : IfcBoolean;
ParentCurve : IfcCurve;
INVERSE
UsingCurves : SET [1:?] OF IfcCompositeCurve FOR Segments;
DERIVE
Dim : IfcDimensionCount := ParentCurve.Dim;
WHERE
ParentIsBoundedCurve : ('IFCGEOMETRYRESOURCE.IfcBoundedCurve' IN TYPEOF(ParentCurve));
END_ENTITY;

EXPRESS-G diagram

`

References: IfcCompositeCurve

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