|Aussparung / Abzugskörper|
A voiding feature is a modification of an element which reduces its volume. Such a feature may be manufactured in different ways, for example by cutting, drilling, or milling of members made of various materials, or by inlays into the formwork of cast members made of materials such as concrete.
The standard use of instances of IfcVoidingFeature is as a part of element type objects (instances of subtypes of IfcElementType). The part–whole relationship is established by an aggregation relationship object, expressing the decomposition of an element type into one or more additive elements (element parts) and zero or more feature elements.
HISTORY New entity in IFC4.
Containment Use Definition
Voiding features shall have no spatial containment relationship to the spatial structure since they are dependent on element types without spatial containment relationships or on an element occurrence with own spatial containment relationship.
- The SELF\IfcElement.ContainedInStructure relationship shall be NIL.
Common Use Definitions
The following concepts are inherited at supertypes:
Property Sets for Objects
The Property Sets for Objects concept applies to this entity as shown in Table 677.
Table 677 — IfcVoidingFeature Property Sets for Objects
The Product Placement concept applies to this entity as shown in Table 678.
Table 678 — IfcVoidingFeature Product Placement
The local placement for IfcVoidingFeatureElement 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.
- In case of features which are part of an element type, absolute placement into the type object's implied coordinate system shall be used.
- In case of features which are voiding an element occurrence, the PlacementRelTo relationship of IfcLocalPlacement shall point to the local placement of the respective element.
The Profile Geometry concept applies to this entity as shown in Table 679.
| || || ||Symbolic representations may be used for simple shapes such as holes or edge features.|
Table 679 — IfcVoidingFeature Profile Geometry
The Surface Geometry concept applies to this entity as shown in Table 680.
Table 680 — IfcVoidingFeature Surface Geometry
The Body Geometry concept applies to this entity as shown in Table 681.
| || || ||Volumetric representations may be used to semi-parametrically model the actual volume of the void created by the feature. Attributes in the shape model directly correspond with feature parameters, for example diameter of circular holes or length and width of cutouts. The objects within the shape model of the feature's shape representation can be included into a CSG model within a representation map of the parent element type.|
Table 681 — IfcVoidingFeature Body Geometry
XSD Specification: <xs:element name="IfcVoidingFeature" type="ifc:IfcVoidingFeature" substitutionGroup="ifc:IfcFeatureElementSubtraction" nillable="true"/>
<xs:attribute name="PredefinedType" type="ifc:IfcVoidingFeatureTypeEnum" use="optional"/>
|HasObjectType|| : ||NOT EXISTS(PredefinedType) OR (PredefinedType <> IfcVoidingFeatureTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);|
|PredefinedType|| : ||Qualifies the feature regarding its shape and configuration relative to the voided element.|
|HasObjectType|| : ||The attribute ObjectType shall be given if the predefined type is set to USERDEFINED.|
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