#### 5.1.3.18 IfcRoot

| Racine
| generelle Basisklasse

IfcRoot is the most abstract and root class for all IFC entity definitions that roots in the kernel or in subsequent layers of the IFC object model. It is therefore the common supertype of all IFC entities, beside those defined in an IFC resource schema. All entities that are subtypes of IfcRoot can be used independently, whereas resource schema entities, that are not subtypes of IfcRoot, are not supposed to be independent entities.

> NOTE View definitions and implementation agreement may impose additional restrictions on the use of the OwnerHistory to handle object versioning.

> HISTORY New entity in IFC1.0

> IFC4 CHANGE The attribute OwnerHistory has been made OPTIONAL.

XSD Specification:

<xs:element name="IfcRoot" type="ifc:IfcRoot" abstract="true" substitutionGroup="ifc:Entity" nillable="true"/>
<xs:complexType name="IfcRoot" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:Entity">
<xs:sequence>
<xs:element name="OwnerHistory" type="ifc:IfcOwnerHistory" nillable="true" minOccurs="0"/>
</xs:sequence>
<xs:attribute name="GlobalId" type="ifc:IfcGloballyUniqueId" use="optional"/>
<xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="Description" type="ifc:IfcText" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcRoot

| ABSTRACT SUPERTYPE OF(ONEOF(IfcObjectDefinition, IfcRelationship));

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| UNIQUE

UR1 | : | GlobalId;

END_ENTITY;

Attribute Definitions:

GlobalId | : | Assignment of a globally unique identifier within the entire software world.
OwnerHistory | : | Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification. IFC4 CHANGE The attribute has been changed to be OPTIONAL.
Name | : | Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.
Description | : | Optional description, provided for exchanging informative comments.

Inheritance Graph:

ENTITY IfcRoot

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

END_ENTITY;

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