IfcStructuralPointAction

Definition from IAI: Instances of the entity IfcStructuralPointAction are used to define point actions. Structural loads applicable to point actions are IfcStructuralLoadSingleForce (and subtype), and IfcStructuralLoadSingleDisplacement (and subtype).

The structural load, defining the point action is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct.

> HISTORY: New entity in Release IFC2x Edition 2.

Topology Use Definition

Special case: If applied to building elements, placement and representation of the structural action are often implied by those of the building elements and are therefore optional for the actions.

Standard case: If applied to structural items, instances of IfcStructuralPointAction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type "IfcTopologyRepresentation".

Placement

The placement for IfcStructuralPointAction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load.

- If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates.
- If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates.
  - If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system.
  - If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.

Topology Representation

Instances of IfcStructuralPointAction may have a topology representation given by a vertex with an optional additional geometric representation by a Cartesian point. It can be provided by either

- IfcVertex
- IfcVertexPoint

which should be the single item of IfcTopologyRepresentation.Items. If no topology representation is given, the location of the placement is taken as the vertex at which the point actions acts upon the structural item.

EXPRESS specification:

ENTITY IfcStructuralPointAction
SUBTYPE OF ( | IfcStructuralAction);
WHERE
WR61 | : | SIZEOF(['IFCSTRUCTURALLOADRESOURCE.IFCSTRUCTURALLOADSINGLEFORCE', 'IFCSTRUCTURALLOADRESOURCE.IFCSTRUCTURALLOADSINGLEDISPLACEMENT'] * TYPEOF(SELF\IfcStructuralActivity.AppliedLoad)) = 1;
END_ENTITY;

Formal Propositions:

WR61 | : | A structural point action should place either a single force, or a single displacement.

Inheritance graph

ENTITY IfcStructuralPointAction;
ENTITY IfcRoot;
GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;
ENTITY IfcObjectDefinition;
INVERSE
HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
IsDecomposedBy | : | SET OF IfcRelDecomposes FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelDecomposes FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject;
ObjectType | : | OPTIONAL IfcLabel;
INVERSE
IsDefinedBy | : | SET OF IfcRelDefines FOR RelatedObjects;
ENTITY IfcProduct;
ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcStructuralActivity;
AppliedLoad | : | IfcStructuralLoad;
GlobalOrLocal | : | IfcGlobalOrLocalEnum;
INVERSE
AssignedToStructuralItem | : | IfcRelConnectsStructuralActivity FOR RelatedStructuralActivity;
ENTITY IfcStructuralAction;
DestabilizingLoad | : | BOOLEAN;
CausedBy | : | OPTIONAL IfcStructuralReaction;
ENTITY IfcStructuralPointAction;
END_ENTITY;