 | Lastfall |
 | Structural Load Case |
| Item | SPF | XML | Change | Description | IFC2x3 to IFC4 |
|---|---|---|---|---|
| IfcStructuralLoadCase | ADDED |
A load case is a load group, commonly used to group loads from the same action source.
HISTORY New entity in IFC4.
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| 11 | SelfWeightCoefficients | IfcRatioMeasure | ? L[3:3] |
The self weight coefficients specify ratios at which loads due to weight of members shall be included in the load case. These loads are not explicitly modeled as instances of IfcStructuralAction. Instead they shall be calculated according to geometry, section, and material of each member.
The three components of the self weight vector correspond with the x,y,z directions of the so-called global coordinates, i.e. the directions of the shared ObjectPlacement of all items in an IfcStructuralAnalysisModel. For example, if the object placement defines a z axis which is upright like the IfcProject's world coordinate system, then the self weight coefficients would typically be [0.,0.,-1.] in a load case of dead loads with self weight. The overall coefficient in the inherited attribute Coefficient shall not be applied to SelfWeightCoefficients of the same instance of IfcStructuralLoadCase. It only applies to actions and load groups which are grouped below the load case, not to the load case's computed self weight. | X |
| Rule | Description |
|---|---|
| IsLoadCasePredefinedType | An instance of this subtype of structural load group cannot be of any other type than that of a load case. |
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | Assignment of a globally unique identifier within the entire software world. | X | |
| 2 | OwnerHistory | IfcOwnerHistory | ? |
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. | X |
| 3 | Name | IfcLabel | ? | 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. | X |
| 4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @RelatedObjects | S[0:?] | Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups. | X | |
| Nests | IfcRelNests @RelatedObjects | S[0:1] | References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition. | X | |
| IsNestedBy | IfcRelNests @RelatingObject | S[0:?] | References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).
IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition. | X | |
| HasContext | IfcRelDeclares @RelatedDefinitions | S[0:1] | References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.
IFC4 CHANGE The inverse attribute datatype has been added. | X | |
| IsDecomposedBy | IfcRelAggregates @RelatingObject | S[0:?] | References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| Decomposes | IfcRelAggregates @RelatedObjects | S[0:1] | References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| HasAssociations | IfcRelAssociates @RelatedObjects | S[0:?] | Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification. | X | |
| IfcObject | |||||
| 5 | ObjectType | IfcLabel | ? |
The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.
| X |
| IsDeclaredBy | IfcRelDefinesByObject @RelatedObjects | S[0:1] | Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDefinesByObject @RelatingObject | S[0:?] | Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| IsTypedBy | IfcRelDefinesByType @RelatedObjects | S[0:1] | Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.
IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange. | X | |
| IsDefinedBy | IfcRelDefinesByProperties @RelatedObjects | S[0:?] | Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| IfcGroup | |||||
| IsGroupedBy | IfcRelAssignsToGroup @RelatingGroup | S[0:?] | Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.
IFC4 CHANGE The cardinality has been changed from 1..1 to 0..? in order to allow the exchange of a group concept without having already group members assigned. It now also allows the use of many instances of IfcRelAssignsToGroup to assign the group members. The change has been done with upward compatibility for file based exchange. | X | |
| IfcStructuralLoadGroup | |||||
| 6 | PredefinedType | IfcLoadGroupTypeEnum | Selects a predefined type for the load group. It can be differentiated between load groups, load cases, load combinations, or userdefined grouping levels. | X | |
| 7 | ActionType | IfcActionTypeEnum | Type of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE. | X | |
| 8 | ActionSource | IfcActionSourceTypeEnum | Source of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE. | X | |
| 9 | Coefficient | IfcRatioMeasure | ? | Load factor. If omitted, a factor is not yet known or not specified. A load factor of 1.0 shall be explicitly exported as Coefficient = 1.0. | X |
| 10 | Purpose | IfcLabel | ? | Description of the purpose of this instance. Among else, possible values of the Purpose of load combinations are 'SLS', 'ULS', 'ALS' to indicate serviceability, ultimate, or accidental limit state. | X |
| SourceOfResultGroup | IfcStructuralResultGroup @ResultForLoadGroup | S[0:1] | Results which were computed using this load group. | X | |
| LoadGroupFor | IfcStructuralAnalysisModel @LoadedBy | S[0:?] | Analysis models in which this load group is used. | X | |
| IfcStructuralLoadCase | |||||
| 11 | SelfWeightCoefficients | IfcRatioMeasure | ? L[3:3] |
The self weight coefficients specify ratios at which loads due to weight of members shall be included in the load case. These loads are not explicitly modeled as instances of IfcStructuralAction. Instead they shall be calculated according to geometry, section, and material of each member.
The three components of the self weight vector correspond with the x,y,z directions of the so-called global coordinates, i.e. the directions of the shared ObjectPlacement of all items in an IfcStructuralAnalysisModel. For example, if the object placement defines a z axis which is upright like the IfcProject's world coordinate system, then the self weight coefficients would typically be [0.,0.,-1.] in a load case of dead loads with self weight. The overall coefficient in the inherited attribute Coefficient shall not be applied to SelfWeightCoefficients of the same instance of IfcStructuralLoadCase. It only applies to actions and load groups which are grouped below the load case, not to the load case's computed self weight. | X |
Group Assignment
The Group Assignment concept template applies to this entity as shown in Table 644.
| ||||||
Table 644 — IfcStructuralLoadCase Group Assignment |
Instance diagram
<?xml version="1.0"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" uuid="5fb9e3e8-a818-4a25-842e-f1f97d62d20c" name="IfcStructuralLoadCase" status="sample" applicableRootEntity="IfcStructuralLoadCase">
<Applicability uuid="00000000-0000-0000-0000-000000000000" status="sample">
<Template ref="1c17882f-eead-4f88-917e-13fe575351b9" />
<TemplateRules operator="and" />
</Applicability>
<Concepts>
<Concept uuid="b1dd0c8b-0d72-4055-be8d-67e7eae5f26d" name="Group Assignment" status="sample" override="false">
<Template ref="f567967f-5493-44d9-ac51-937c09ac2583" />
<TemplateRules operator="and">
<TemplateRule Description="Structural actions for the load case." Parameters="" />
</TemplateRules>
</Concept>
</Concepts>
</ConceptRoot>
| # | Concept | Template | Model View |
|---|---|---|---|
| IfcRoot | |||
| Identity | Software Identity | General Usage | |
| Revision Control | Revision Control | General Usage | |
| IfcObjectDefinition | |||
| Classification Association | Classification Association | General Usage | |
| IfcObject | |||
| Object User Identity | Object User Identity | General Usage | |
| Object Predefined Type | Object Predefined Type | General Usage | |
| Object Typing | Object Typing | General Usage | |
| Property Sets for Objects | Property Sets for Objects | General Usage | |
| Property Sets with Override | Property Sets with Override | General Usage | |
| IfcStructuralLoadCase | |||
| Group Assignment | Group Assignment | General Usage | |
<xs:element name="IfcStructuralLoadCase" type="ifc:IfcStructuralLoadCase" substitutionGroup="ifc:IfcStructuralLoadGroup" nillable="true"/>
<xs:complexType name="IfcStructuralLoadCase">
<xs:complexContent>
<xs:extension base="ifc:IfcStructuralLoadGroup">
<xs:attribute name="SelfWeightCoefficients" use="optional">
<xs:simpleType>
<xs:restriction>
<xs:simpleType>
<xs:list itemType="ifc:IfcRatioMeasure"/>
</xs:simpleType>
<xs:minLength value="3"/>
<xs:maxLength value="3"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
ENTITY IfcStructuralLoadCase
SUBTYPE OF (IfcStructuralLoadGroup);
SelfWeightCoefficients : OPTIONAL LIST [3:3] OF IfcRatioMeasure;
WHERE
IsLoadCasePredefinedType : SELF\IfcStructuralLoadGroup.PredefinedType = IfcLoadGroupTypeEnum.LOAD_CASE;
END_ENTITY;
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