IfcSurfaceOfLinearExtrusion

BACnet MVD

#### IfcSurfaceOfLinearExtrusion

Natural language names

| Oberfläche - Entlang einem Vektor extrudiert
| Surface Of Linear Extrusion
| Extrusion linéaire ou surfacique

Change log

Item | SPF | XML | Change | Description
--- | --- | --- | --- | ---
IFC2x3 to IFC4
IfcSurfaceOfLinearExtrusion |  |  |  |
Position |  |  | MODIFIED | Instantiation changed to OPTIONAL.

##### Semantic definitions at the entity

Entity definition

The IfcSurfaceOfLinearExtrusion is a surface derived by sweeping a curve along a vector.

> NOTE Definition according to ISO/CD 10303-42:1992
> This surface is a simple swept surface or a generalized cylinder obtained by sweeping a curve in a given direction. The parameterization is as follows where the curve has a parameterization λ(u):

> > V = ExtrusionAxis

> The parameterization range for v is -∞ < v < ∞ and for u it is defined by the curve parameterization.

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

> HISTORY New entity in IFC2x.

Informal Propositions:

1. The surface shall not self-intersect

Attribute definitions

# | Attribute | Type | Cardinality | Description | B
--- | --- | --- | --- | --- | ---
3 | ExtrudedDirection | IfcDirection |  | The direction of the extrusion. | X | X
4 | Depth | IfcLengthMeasure |  | The depth of the extrusion, it determines the parameterization. | X | X
| ExtrusionAxis :=IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth) | IfcVector |  | The extrusion axis defined as vector. | X | X

##### 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
IfcSurface

Dim
:=3

IfcDimensionCount

The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.

> IFC4 CHANGE Derived attribute promoted from subtypes.

X

X

IfcSweptSurface
1 | SweptCurve | IfcProfileDef |  | The curve to be swept in defining the surface. The curve is defined as a profile within the position coordinate system. | X | X

2

Position

IfcAxis2Placement3D

?

Position coordinate system for the swept surface, provided by a profile definition within the XY plane of the Position coordinates. If not provided, the position of the profile being swept is determined by the object coordinate system. In this case, the swept surface is not repositioned.

> IFC4 CHANGE The attribute has been changed to OPTIONAL with upward compatibility for file-based exchange.

X

IfcSurfaceOfLinearExtrusion
3 | ExtrudedDirection | IfcDirection |  | The direction of the extrusion. | X | X
4 | Depth | IfcLengthMeasure |  | The depth of the extrusion, it determines the parameterization. | X | X
| ExtrusionAxis :=IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth) | IfcVector |  | The extrusion axis defined as vector. | X | X

##### Formal representations

XML Specification
`<xs:element name="IfcSurfaceOfLinearExtrusion" type="ifc:IfcSurfaceOfLinearExtrusion" substitutionGroup="ifc:IfcSweptSurface" nillable="true"/>
<xs:complexType name="IfcSurfaceOfLinearExtrusion">
<xs:complexContent>
<xs:extension base="ifc:IfcSweptSurface">
<xs:sequence>
<xs:element name="ExtrudedDirection" type="ifc:IfcDirection" nillable="true"/>
</xs:sequence>
<xs:attribute name="Depth" type="ifc:IfcLengthMeasure" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
`
EXPRESS Specification
`ENTITY IfcSurfaceOfLinearExtrusion
SUBTYPE OF (IfcSweptSurface);
ExtrudedDirection : IfcDirection;
Depth : IfcLengthMeasure;
DERIVE
ExtrusionAxis : IfcVector := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcVector (ExtrudedDirection, Depth);
WHERE
DepthGreaterZero : Depth > 0.;
END_ENTITY;

EXPRESS-G diagram

`

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