IFC 4.3.0.1 (IFC4X3) development

8.9.3.56 IfcRectangularTrimmedSurface

8.9.3.56.1 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.

8.9.3.56.2 Entity inheritance

8.9.3.56.3 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 8.9.3.56.A

8.9.3.56.4 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_cedaad7e.IFCELEMENTARYSURFACE' IN TYPEOF(BasisSurface)) AND
         (NOT ('IFC4X3_DEV_cedaad7e.IFCPLANE' IN TYPEOF(BasisSurface)))) OR
         ('IFC4X3_DEV_cedaad7e.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 8.9.3.56.B

8.9.3.56.5 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_cedaad7e.IFCELEMENTARYSURFACE' IN TYPEOF(BasisSurface)) AND
         (NOT ('IFC4X3_DEV_cedaad7e.IFCPLANE' IN TYPEOF(BasisSurface)))) OR
         ('IFC4X3_DEV_cedaad7e.IFCSURFACEOFREVOLUTION' IN TYPEOF(BasisSurface)) OR
         (Usense = (U2 > U1));
	V1AndV2Different : V1 <> V2;
	VsenseCompatible : Vsense = (V2 > V1);
END_ENTITY;

8.9.3.56.6 References

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8.9.3.56.7 Changelog

  • 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"