IFC 4.3.2.20240512 (IFC4X3_ADD2) under development

8.9.3.55 IfcRectangularTrimmedSurface

8.9.3.55.1 Semantic definition

The IfcRectangularTrimmedSurface is a surface created by bounding its BasisSurface along two pairs of parallel curves defined within the parametric space of the referenced surface.

Informal Propositions

  1. The domain of the trimmed surface shall be within the domain of the surface being trimmed.

8.9.3.55.2 Entity inheritance

8.9.3.55.3 Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

StyledByItem SET [0:1] OF IfcStyledItem FOR Item

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

IfcSurface (1)
* Dim IfcDimensionCount

This attribute is formally derived.

3

The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.

Click to show 3 hidden inherited attributes Click to hide 3 inherited attributes
IfcRectangularTrimmedSurface (7)
1 BasisSurface IfcSurface

Surface being trimmed.

2 U1 IfcParameterValue

First u parametric value.

3 V1 IfcParameterValue

First v parametric value.

4 U2 IfcParameterValue

Second u parametric value.

5 V2 IfcParameterValue

Second v parametric value.

6 Usense IfcBoolean

Flag to indicate whether the direction of the first parameter of the trimmed surface agrees with or opposes the sense of u in the basis surface.

7 Vsense IfcBoolean

Flag to indicate whether the direction of the second parameter of the trimmed surface agrees with or opposes the sense of v in the basis surface.

Table 8.9.3.55.A

8.9.3.55.4 Formal propositions

Name Description
U1AndU2Different

U1 and U2 shall have different values.

U1 <> U2
UsenseCompatible

With exception of those surfaces closed in the U parameter, direction Usense shall be compatible with the ordered parameter values for U.

(('IFC4X3_DEV_0078979.IFCELEMENTARYSURFACE' IN TYPEOF(BasisSurface)) AND
         (NOT ('IFC4X3_DEV_0078979.IFCPLANE' IN TYPEOF(BasisSurface)))) OR
         ('IFC4X3_DEV_0078979.IFCSURFACEOFREVOLUTION' IN TYPEOF(BasisSurface)) OR
         (Usense = (U2 > U1))
V1AndV2Different

V1 and V2 shall have different values.

V1 <> V2
VsenseCompatible

Vsense shall be compatible with the ordered parameter values for V.

Vsense = (V2 > V1)
Table 8.9.3.55.B

8.9.3.55.5 Formal representation

ENTITY IfcRectangularTrimmedSurface
 SUBTYPE OF (IfcBoundedSurface);
	BasisSurface : IfcSurface;
	U1 : IfcParameterValue;
	V1 : IfcParameterValue;
	U2 : IfcParameterValue;
	V2 : IfcParameterValue;
	Usense : IfcBoolean;
	Vsense : IfcBoolean;
 WHERE
	U1AndU2Different : U1 <> U2;
	UsenseCompatible : (('IFC4X3_DEV_0078979.IFCELEMENTARYSURFACE' IN TYPEOF(BasisSurface)) AND
         (NOT ('IFC4X3_DEV_0078979.IFCPLANE' IN TYPEOF(BasisSurface)))) OR
         ('IFC4X3_DEV_0078979.IFCSURFACEOFREVOLUTION' IN TYPEOF(BasisSurface)) OR
         (Usense = (U2 > U1));
	V1AndV2Different : V1 <> V2;
	VsenseCompatible : Vsense = (V2 > V1);
END_ENTITY;

8.9.3.55.6 References

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8.9.3.55.7 Changelog

8.9.3.55.7.1 IFC4

  • where rule, U1AndU2Different
  • where rule, UsenseCompatible
  • where rule, V1AndV2Different
  • where rule, VsenseCompatible
  • where rule, WR1
  • where rule, WR2
  • where rule, WR3
  • where rule, WR4
  • attribute Usense type, Changed from "boolean" to "IfcBoolean"
  • attribute Vsense type, Changed from "boolean" to "IfcBoolean"