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IfcLightFixture

Definition from IAI: Electrically powered fixture that provides illuminence.

HISTORY: New entity in IFC R2.0
ISSUES: See issues and change log for changes made in IFC R2x.

Geometry Use Definitions

The geometric representation of IfcLightFixture is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are:

Local Placement

The local placement is defined in the supertype IfcProduct. It is defined by a subtype of IfcObjectPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. The PlacementRelTo relationship of IfcLocalPlacement, if given, shall point to the same IfcSpatialStructureElement which is used in the ContainedInStructure inverse attribute, or to a referenced spatial structure element at a higher level. If the relative placement is not used, the absolute placement is defined within the world coordinate system.

Informal propositions for local placement:

  1. If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement.

Standard Geometric Representation

Currently, the use of attribute driven geometry for this class is not supported. The standard geometric representation is defined using explicit geometry.

B-Rep Representation

The faceted B-Rep capabilities (with or without voids) shall be supported for B-Rep representation.


EXPRESS specification:

ENTITY IfcLightFixture
SUBTYPE OF ( IfcElectricalElement);
MaximumSpaceSensibleLoad  :  OPTIONAL IfcPowerMeasure;
MaximumPlenumSensibleLoad_  :  OPTIONAL IfcPowerMeasure;
SensibleLoadToRadiant  :  OPTIONAL IfcPositiveRatioMeasure;
END_ENTITY;

Attribute definitions:

MaximumSpaceSensibleLoad  :  Maximum or Peak sensible thermal load contributed to the conditioned space by the light fixture.
MaximumPlenumSensibleLoad_  :  Maximum or Peak sensible thermal load contributed to return air plenum by the light fixture.
SensibleLoadToRadiant  :  Percent of sensible thermal load to radiant heat.

References (1):

Name Type Referred through Express-G
IfcElectricalElement Entity
Subtype
Diagram 1

Inheritance graph

ENTITY IfcLightFixture;
ENTITY IfcRoot;
GlobalId  :  IfcGloballyUniqueId;
OwnerHistory  :  IfcOwnerHistory;
Name  :  OPTIONAL IfcLabel;
Description  :  OPTIONAL IfcText;
ENTITY IfcObject;
ObjectType  :  OPTIONAL IfcLabel;
INVERSE
IsDefinedBy  :  SET OF IfcRelDefines FOR RelatedObjects;
HasAssociations  :  SET OF IfcRelAssociates FOR RelatedObjects;
HasAssignments  :  SET OF IfcRelAssigns FOR RelatedObjects;
Decomposes  :  SET OF IfcRelDecomposes FOR RelatedObjects;
IsDecomposedBy  :  SET [0:1] OF IfcRelDecomposes FOR RelatingObject;
ENTITY IfcProduct;
ObjectPlacement  :  OPTIONAL IfcObjectPlacement;
Representation  :  OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy  :  SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcElement;
Tag  :  OPTIONAL IfcIdentifier;
INVERSE
ConnectedTo  :  SET OF IfcRelConnectsElements FOR RelatingElement;
ConnectedFrom  :  SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure  :  SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
ENTITY IfcLightFixture;
MaximumSpaceSensibleLoad  :  OPTIONAL IfcPowerMeasure;
MaximumPlenumSensibleLoad_  :  OPTIONAL IfcPowerMeasure;
SensibleLoadToRadiant  :  OPTIONAL IfcPositiveRatioMeasure;
END_ENTITY;