Natural language names
 | Beschränkung |
 | Constraint |
 | Contrainte |
| Beschränkung |
| Constraint |
| Contrainte |
An IfcConstraint is used to define a constraint or limiting value or boundary condition that may be applied to an object or to the value of a property.
Constraints may be subdivided into user-defined constraints and system-defined constraints. User-defined constraints are applied by a user and are restricted to high-level definitions such as object properties. System-defined constraints may apply to any object attribute, are typically defined by an application to enforce data validation or parametric behavior, and are intended to be enforced by applications but not to be directly editable by an end-user.
IfcConstraint may be associated with any subtype of IfcObjectDefinition or IfcPropertyDefinition through the IfcRelAssociatesConstraint relationship to indicate a system-defined constraint, or may be associated with IfcResourceObjectSelect (such as IfcPropertySingleValue) by IfcResourceConstraintRelationship to indicate a user-defined constraint.
A constraint must have a name applied through the IfcConstraint.Name attribute and optionally, a description through IfcConstraint.Description. The grade of the constraint (hard, soft, advisory) must be specified through IfcConstraint.ConstraintGrade or IfcConstraint.UserDefinedGrade whilst the source, creating actor and time at which the constraint is created may be optionally asserted through IfcConstraint.ConstraintSource, IfcConstraint.CreatingActor and IfcConstraint.CreationTime.
A constraint may also have additional external information (such as classification or document information) associated to it by IfcExternalReferenceRelationship, accessible through inverse attribute IfcConstraint.HasExternalReferences
HISTORY New entity in IFC2.0
IFC4 CHANGE CreationTime changed to IfcDateTime for ISO 8601 representation, HasExternalReferences new inverse attribute.
| # | Attribute | Type | Cardinality | Description | B |
|---|---|---|---|---|---|
| 1 | Name | IfcLabel | [1:1] | A human-readable name to be used for the constraint. | X |
| 2 | Description | IfcText | [0:1] | A human-readable description that may apply additional information about a constraint. | X |
| 3 | ConstraintGrade | IfcConstraintEnum | [1:1] | Enumeration that qualifies the type of constraint. | X |
| 4 | ConstraintSource | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 5 | CreatingActor | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 6 | CreationTime | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 7 | UserDefinedGrade | - | This attribute is out of scope for this model view definition and shall not be set. |
| Rule | Description |
|---|---|
| WR11 | The attribute UserDefinedGrade must be asserted when the value of the IfcConstraintGradeEnum is set to USERDEFINED. |
| # | Attribute | Type | Cardinality | Description | B |
|---|---|---|---|---|---|
| IfcConstraint | |||||
| 1 | Name | IfcLabel | [1:1] | A human-readable name to be used for the constraint. | X |
| 2 | Description | IfcText | [0:1] | A human-readable description that may apply additional information about a constraint. | X |
| 3 | ConstraintGrade | IfcConstraintEnum | [1:1] | Enumeration that qualifies the type of constraint. | X |
| 4 | ConstraintSource | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 5 | CreatingActor | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 6 | CreationTime | - | This attribute is out of scope for this model view definition and shall not be set. | ||
| 7 | UserDefinedGrade | - | This attribute is out of scope for this model view definition and shall not be set. | ||
<xs:element name="IfcConstraint" type="ifc:IfcConstraint" abstract="true" substitutionGroup="ifc:Entity" nillable="true"/>
<xs:complexType name="IfcConstraint" abstract="true">
<xs:complexContent>
<xs:extension base="ifc:Entity">
<xs:attribute name="Name" type="ifc:IfcLabel" use="optional"/>
<xs:attribute name="Description" type="ifc:IfcText" use="optional"/>
<xs:attribute name="ConstraintGrade" type="ifc:IfcConstraintEnum" use="optional"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcConstraint
ABSTRACT SUPERTYPE OF(ONEOF(IfcMetric, IfcObjective));
Name : IfcLabel;
Description : OPTIONAL IfcText;
ConstraintGrade : IfcConstraintEnum;
ConstraintSource : OPTIONAL IfcStrippedOptional;
CreatingActor : OPTIONAL IfcStrippedOptional;
CreationTime : OPTIONAL IfcStrippedOptional;
UserDefinedGrade : OPTIONAL IfcStrippedOptional;
INVERSE
WHERE
WR11 : (ConstraintGrade <> IfcConstraintEnum.USERDEFINED) OR
((ConstraintGrade = IfcConstraintEnum.USERDEFINED) AND EXISTS(SELF\IfcConstraint.UserDefinedGrade));
END_ENTITY;
EXPRESS-G diagram
Link to this page