|Modifikator (geometrischer Körper) - Subtraktion|
The IfcFeatureElementSubtraction is specialization of
the general feature element, that represents an existence dependent
elements which modifies the shape and appearance of the associated
master element. The IfcFeatureElementSubtraction offers the
ability to handle shape modifiers as semantic objects within the
IFC object model that subtract from the shape of the master
NOTE A single subtraction feature
such as the subtype IfcOpeningElement is assigned by a
single subtraction relationship IfcRelVoidsElement to one
occurrences of IfcElement. It establishes a 1:1
relationship between the opening and the element. An element may
have several IfcRelVoidsElement relationships, enabling
The voiding relationship between a master element and a
subtraction feature is geometrically resolved by a Boolean
HISTORY New entity in IFC2x2.
IFC2x2 CHANGE The entity is introduced as an upward compatible extension of the IFC2x
platform. It is an intermediate abstract supertype without defining its own explicit attributes.
Geometry Use Definitions
The geometric representation of
IfcFeatureElementSubtraction is given by the
IfcProductDefinitionShape, allowing multiple geometric
The local placement for IfcFeatureElementSubtraction is
defined in its supertype IfcProduct. It is defined by the
IfcLocalPlacement, which defines the local coordinate system
that is referenced by all geometric representations. The local
placement is always defined in relation to the local placement of
the building element from which the feature element substration is
- The PlacementRelTo relationship of
IfcLocalPlacement shall point (if given) to the local
placement of the same IfcElement, which is used in the
VoidsElements.RelatingElement inverse attribute.
The geometry use definitions for the shape representation of the
IfcFeatureElementSubtraction is given at the level of its
XSD Specification: <xs:element name="IfcFeatureElementSubtraction" type="ifc:IfcFeatureElementSubtraction" abstract="true" substitutionGroup="ifc:IfcFeatureElement" nillable="true"/>
<xs:complexType name="IfcFeatureElementSubtraction" abstract="true">
|HasNoSubtraction|| : ||SIZEOF(SELF\IfcElement.HasOpenings) = 0;|
|IsNotFilling|| : ||SIZEOF(SELF\IfcElement.FillsVoids) = 0;|
|VoidsElements|| : ||Reference to the Voids Relationship that uses this Opening Element to create a void within an Element. The Opening Element can only be used to create a single void within a single Element.
|HasNoSubtraction|| : ||
An feature subtraction (e.g. an opening element) can not have other openings to void itself. The inverse relationship HasOpenings shall therefore be NIL.
|IsNotFilling|| : ||
An feature subtraction (e.g. an opening element) can not be a filling of another void. The inverse relationship FillsVoids shall therefore be NIL.
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