Voids

Overview

Describes a relationship in which a feature element (either an opening element or an edge feature) subtracts material from another element (which may be a building element or other subtype of element).
To ensure that there is clarity about entities that are participating in the voiding relationship, reference to this functional part within the IDM will indicate parameters for the aggregation as:
--->> fp_voids (element, feature_element_subtraction_type)

where the feature element subtraction type is either an opening or an edge feature.

Results

Declares the existence of a specific voiding relationship

Description	Entity/Pset/Functional Part	MAN	REC	OPT
Set the occurrence of the element in which the void is to be created	IfcElement
Set the occurrence of the feature element subtraction that will create the void	IfcOpeningElement OR IfcEdgeFeature
Assert the relationship to the element	IfcRelVoids.RelatingBuildingElement
Assert the relationship to the feature creating the void	IfcRelVoids.RelatedOpeningElement

IFC Entities Required

IfcElement
IfcFeatureElement
IfcFeatureElementSubtraction
IfcObject
IfcProduct
IfcRelationship
IfcRelConnects
IfcRelVoids
IfcRoot

IFC Datatypes Required

IfcGloballyUniqueId
IfcIdentifier
IfcLabel
IfcText

IFC Functions Required

-

IFC Property Sets Required

-

IDM Functional Parts Required

fp_apply_owner_history

EXPRESS Schema

SCHEMA FP_VOIDS;

  TYPE IfcGloballyUniqueId = STRING (22) FIXED;
  END_TYPE;

  TYPE IfcIdentifier = STRING;
  END_TYPE;

  TYPE IfcLabel = STRING;
  END_TYPE;

  TYPE IfcText = STRING;
  END_TYPE;

  ENTITY IfcProduct
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcObject);
    WHERE
      WR1 : (EXISTS(Representation) AND EXISTS(ObjectPlacement))
            OR (EXISTS(Representation) AND 
            (NOT('IFC2X2_FINAL.IFCPRODUCTDEFINITIONSHAPE' IN TYPEOF(Representation))))
            OR (NOT(EXISTS(Representation)));
  END_ENTITY;

  ENTITY IfcObject
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcRoot);
      ObjectType : OPTIONAL IfcLabel;
    WHERE
      WR1 : SIZEOF(QUERY(temp <* IsDefinedBy | 'IFC2X2_FINAL.IFCRELDEFINESBYTYPE' IN TYPEOF(temp))) <= 1;
  END_ENTITY;

  ENTITY IfcRoot
    ABSTRACT SUPERTYPE OF (ONEOF(IfcObject, IfcRelationship));
      GlobalId      : IfcGloballyUniqueId;
      Name          : OPTIONAL IfcLabel;
      Description   : OPTIONAL IfcText;
      xOwnerHistory : fp_apply_owner_history;
    UNIQUE
      UR1 : GlobalId;
  END_ENTITY;

  ENTITY IfcRelationship
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcRoot);
  END_ENTITY;

  ENTITY IfcRelConnects
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcRelationship);
  END_ENTITY;

  ENTITY IfcElement
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcProduct);
      Tag         : OPTIONAL IfcIdentifier;
    INVERSE
      HasOpenings : SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
  END_ENTITY;

  ENTITY IfcFeatureElement
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcElement);
  END_ENTITY;

  ENTITY IfcFeatureElementSubtraction
    ABSTRACT SUPERTYPE
    SUBTYPE OF(IfcFeatureElement);
    INVERSE
      VoidsElements : IfcRelVoidsElement FOR RelatedOpeningElement;
  END_ENTITY;

  ENTITY IfcRelVoidsElement
    SUBTYPE OF(IfcRelConnects);
      RelatingBuildingElement : IfcElement;
      RelatedOpeningElement   : IfcFeatureElementSubtraction;
  END_ENTITY;

  ENTITY fp_apply_owner_history;
  END_ENTITY;

END_SCHEMA;

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