IFC 4.3.0.1 (IFC4X3) development

# 7.10.3.28 IfcStructuralSurfaceReaction

## 7.10.3.28.1 Semantic definition

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

*Coordinate Systems*:

See definitions at IfcStructuralActivity.

*Topology Use Definitions*:

See definitions at IfcStructuralActivity.

Informal Propositions:

1. If the surface reaction is of the predefined type CONST, SELF\IfcStructuralActivity.AppliedLoad must not be of type IfcStructuralLoadConfiguration.
2. If the surface reaction is of the predefined type BILINEAR, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain three items with two-dimensional IfcStructuralLoadConfiguration.Locations, defining the location of the result samples in local coordinates of the surface reaction.
3. If the surface reaction is of the predefined type DISCRETE, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain two or more items with two-dimensional locations.
4. If the surface reaction is of the predefined type ISOCONTOUR, SELF\IfcStructuralActivity.AppliedLoad shall be of type IfcStructuralLoadConfiguration and shall contain the same number of items as the set SELF.IfcProduct.Representation.Representations[?].Items. Each item in the load configuration shall have a two-dimensional location, defining the location of the result samples in local coordinates of the surface reaction. Each item in SELF\IfcStructuralActivity.AppliedLoad shall be located at exactly one of the isocontours.
NOTE The set of representation items is unordered, hence result locations are required to correlate result values and isocontours.
NOTE Isocontours are represented as IfcPCurves which are defined in terms of surface parameters u,v, while result locations are given in local surface item coordinates x,y. It is strongly recommended that the surface parameterization u,v is scaled 1:1 in order to avoid different scales of u,v versus x,y. If u,v are scaled 1:1 and the IfcPCurve's base surface is identical with the surface item's base surface, u,v and local x,y are identical.
5. All items in SELF\IfcStructuralActivity.AppliedLoad\IfcStructuralLoadConfiguration.Values shall be of the same entity type.

## 7.10.3.28.5 Property sets

• Pset_Risk
• RiskName
• RiskType
• NatureOfRisk
• RiskAssessmentMethodology
• UnmitigatedRiskLikelihood
• UnmitigatedRiskConsequence
• UnmitigatedRiskSignificance
• MitigationPlanned
• MitigatedRiskLikelihood
• MitigatedRiskConsequence
• MitigatedRiskSignificance
• MitigationProposed
• AssociatedProduct
• AssociatedActivity
• AssociatedLocation
• Pset_Tolerance
• ToleranceDescription
• ToleranceBasis
• OverallTolerance
• HorizontalTolerance
• OrthogonalTolerance
• VerticalTolerance
• PlanarFlatness
• HorizontalFlatness
• ElevationalFlatness
• SideFlatness
• OverallOrthogonality
• HorizontalOrthogonality
• OrthogonalOrthogonality
• VerticalOrthogonality
• OverallStraightness
• HorizontalStraightness
• OrthogonalStraightness
• VerticalStraightness
• Pset_Uncertainty
• UncertaintyBasis
• UncertaintyDescription
• HorizontalUncertainty
• LinearUncertainty
• OrthogonalUncertainty
• VerticalUncertainty
• Qto_BodyGeometryValidation
• GrossSurfaceArea
• NetSurfaceArea
• GrossVolume
• NetVolume
• SurfaceGenusBeforeFeatures
• SurfaceGenusAfterFeatures

## 7.10.3.28.7 Formal representation

ENTITY IfcStructuralSurfaceReaction
SUBTYPE OF (IfcStructuralReaction);
PredefinedType : IfcStructuralSurfaceActivityTypeEnum;
WHERE
HasPredefinedType : (PredefinedType <> IfcStructuralSurfaceActivityTypeEnum.USERDEFINED) OR EXISTS(SELF\IfcObject.ObjectType);
END_ENTITY;