IFC 4.3.x development

7.11.3.12 IfcStructuralCurveReaction

Change log

IFC4

added

7.11.3.12.1 Semantic definitions at the entity

This entity defines a reaction which occurs distributed over a curve. A curve reaction may be connected with a curve member or curve connection, or surface member or surface connection.

HISTORY  New entity in IFC4.

*Coordinate Systems*:

See definitions at IfcStructuralActivity.

*Topology Use Definitions*:

Standard Case:
If connected with a curve item, instances of IfcStructuralCurveRection shall not have an ObjectPlacement nor a Representation. It is implied that the placement and representation of the IfcStructuralActivity is the same as the ones of the member or connection.

Special Case:
If connected with a surface item, instances of IfcStructuralCurveReaction shall have an ObjectPlacement and Representation, containing an IfcEdgeCurve. See IfcStructuralActivity for further definitions.

Informal Propositions:

  1. If the curve reaction is of the predefined type CONST, SELF\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration.
  2. If the curve reaction is of the predefined type LINEAR, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two items.
  3. If the curve reaction is of the predefined type POLYGONAL, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three or more items.
  4. If the curve action is of the predefined type DISCRETE, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items.
  5. In case of types LINEAR, POLYGONAL, and DISCRETE, the load items shall have one-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the result samples in local coordinates of the curve reaction. The load items shall be provided in ascending order according to their locations. The first and the last load item define the extent of the result distribution.
  6. If the curve reaction is of the predefined type EQUIDISTANT, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items. IfcStructuralLoadConfiguration.Locations shall be omitted as it is implicit. The load items shall be provided in ascending order. The first and the last load item are located at the beginning and end of the result distribution, respectively.
  7. All items in SELF\IfcStructuralActivity.AppliedLoad\IfcStructuralLoadConfiguration.Values shall be of the same entity type.

7.11.3.12.1 Attributes

# Attribute Type Description
IfcRoot
1 GlobalId IfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world.
2 OwnerHistory OPTIONAL 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.
3 Name OPTIONAL 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.
4 Description OPTIONAL IfcText Optional description, provided for exchanging informative comments.
IfcObjectDefinition
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects 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.
Nests SET [0:1] OF IfcRelNests FOR RelatedObjects 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.
IsNestedBy SET [0:?] OF IfcRelNests FOR RelatingObject 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.
HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions 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.
IsDecomposedBy SET [0:?] OF IfcRelAggregates FOR RelatingObject 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.
Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects 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.
HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects 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.
IfcObject
5 ObjectType OPTIONAL 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.
IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects 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.
Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject 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.
IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects 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.
IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects 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.
IfcProduct
6 ObjectPlacement OPTIONAL IfcObjectPlacement Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system.
7 Representation OPTIONAL IfcProductRepresentation Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement.
ReferencedBy SET [0:?] OF IfcRelAssignsToProduct FOR RelatingProduct Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product.
PositionedRelativeTo SET [0:?] OF IfcRelPositions FOR RelatedProducts
ReferencedInStructures SET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements
IfcStructuralActivity
8 AppliedLoad IfcStructuralLoad Load or result resource object which defines the load type, direction, and load values.

In case of activities which are variably distributed over curves or surfaces, IfcStructuralLoadConfiguration is used which provides a list of load samples and their locations within the load distribution, measured in local coordinates of the curve or surface on which this activity acts. The contents of this load or result distribution may be further restricted by definitions at subtypes of IfcStructuralActivity.
9 GlobalOrLocal IfcGlobalOrLocalEnum Indicates whether the load directions refer to the global coordinate system (global to

the analysis model, i.e. as established by _IfcStructuralAnalysisModel.SharedPlacement_)

or to the local coordinate system (local to the activity or connected item, as established by

an explicit or implied representation and its parameter space).

> NOTE , the informal definition of _IfcRepresentationResource.IfcGlobalOrLocalEnum_ doe s not distinguish between "global coordinate system" and "world coordinate system". On the other hand, this distinction is necessary in the IfcStructuralAnalysisDomain where the shared "global" coordinate system of an analysis model may very well not be the same as the project-wide world coordinate system.

> NOTE  In the scope of _IfcStructuralActivity.GlobalOrLocal_, the meaning of GLOBAL_COORDS is therefore not to be taken as world coordinate system but as the analysis model specific shared coordinate system. In contrast, LOCAL_COORDS is to be taken as coordinates which are local to individual structural items and activities, as established by subclass-specific geometry use definitions.
AssignedToStructuralItemSET [0:1] OF IfcRelConnectsStructuralActivity FOR RelatedStructuralActivityReference to the IfcRelConnectsStructuralActivity relationship by which activities are connected with structural items.
IfcStructuralReaction
IfcStructuralCurveReaction
10 PredefinedType IfcStructuralCurveActivityTypeEnum Type of reaction according to its distribution of load values.

7.11.3.12.2 Entity inheritance

dot_inheritance IfcStructuralCurveReaction IfcStructuralCurveReaction IfcStructuralReaction IfcStructuralReaction IfcStructuralCurveReaction->IfcStructuralReaction IfcStructuralPointReaction IfcStructuralPointReaction IfcStructuralPointReaction->IfcStructuralReaction IfcStructuralActivity IfcStructuralActivity IfcStructuralReaction->IfcStructuralActivity IfcStructuralSurfaceReaction IfcStructuralSurfaceReaction IfcStructuralSurfaceReaction->IfcStructuralReaction IfcStructuralAction IfcStructuralAction IfcStructuralAction->IfcStructuralActivity IfcProduct IfcProduct IfcStructuralActivity->IfcProduct IfcProduct_children 8 more... IfcProduct_children->IfcProduct IfcObject IfcObject IfcProduct->IfcObject IfcObject_children 5 more... IfcObject_children->IfcObject IfcObjectDefinition IfcObjectDefinition IfcObject->IfcObjectDefinition IfcContext IfcContext IfcContext->IfcObjectDefinition IfcRoot IfcRoot IfcObjectDefinition->IfcRoot IfcTypeObject IfcTypeObject IfcTypeObject->IfcObjectDefinition IfcPropertyDefinition IfcPropertyDefinition IfcPropertyDefinition->IfcRoot IfcRelationship IfcRelationship IfcRelationship->IfcRoot

7.11.3.12.3 Definitions applying to General Usage

7.11.3.12.3.1 Classification Association

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

7.11.3.12.3.2 Identity

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

7.11.3.12.3.3 Object Predefined Type

7.11.3.12.3.4 Object Typing

Any object occurrence can be typed by being assigned to a common object type utilizing this concept. A particular rule, restricting the applicable subtypes of IfcTypeObject that can be assigned, is introduced by overriding this concept at the level of subtypes of IfcObject.

7.11.3.12.3.5 Object User Identity

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as ifcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

7.11.3.12.3.6 Product Geometric Representation

The geometric representation of any IfcProduct is provided by the IfcProductDefinitionShape allowing multiple geometric representations. It uses the Product Placement concept utilizing IfcLocalPlacement to establish an object coordinate system, within all geometric representations are founded.

NOTE  A detailed specification of how to apply the local placement and which shape representaions are applicable is provided at the level of subtypes of IfcProduct and is further determined by the model view definition and implementer agreements.

7.11.3.12.3.7 Product Placement

The Product Placement establishes the object coordinate system and is required, if a geometric shape representation is provided for this product.

7.11.3.12.3.8 Property Sets for Objects

Any object occurrence can hold property sets, each being a set of individual properties having name, description, value(s) and unit(s). A reference to applicable property sets, being part of this specification, is introduced at the level of sub types of IfcObject.

7.11.3.12.3.9 Property Sets with Override

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case, that the same property (within the same property set, is defined both, in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

7.11.3.12.3.10 Revision Control

Ownership, history, and merge state is captured using IfcOwnerHistory.

7.11.3.12.3.11 Structural Activity

RelatingElement AppliedLoad
'IfcStructuralCurveMember''IfcStructuralLoadConfiguration'

7.11.3.12.4 Formal representations

ENTITY IfcStructuralCurveReaction
 SUBTYPE OF (IfcStructuralReaction);
	PredefinedType : IfcStructuralCurveActivityTypeEnum;
 WHERE
	HasObjectType : (PredefinedType <> IfcStructuralCurveActivityTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);
	SuitablePredefinedType : (PredefinedType <> IfcStructuralCurveActivityTypeEnum.SINUS) AND (PredefinedType <> IfcStructuralCurveActivityTypeEnum.PARABOLA);
END_ENTITY;