IFC 4.3.x development

8.9.3.58 IfcRectangularTrimmedSurface

Change log

IFC4

additions where_rules U1AndU2Different
additions where_rules UsenseCompatible
additions where_rules V1AndV2Different
additions where_rules VsenseCompatible
deletions where_rules WR1
deletions where_rules WR2
deletions where_rules WR3
deletions where_rules WR4
modificationsattributes Usense definitionChanged from boolean to IfcBoolean
modificationsattributes Vsense definitionChanged from boolean to IfcBoolean

IFC4X1

modificationswhere_rules UsenseCompatible definitionChanged from (('ifc4.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4.ifcplane' in typeof(BasisSurface)))) or ('ifc4.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1)) to (('ifc4x1.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4x1.ifcplane' in typeof(BasisSurface)))) or ('ifc4x1.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1))

IFC4X2

modificationswhere_rules UsenseCompatible definitionChanged from (('ifc4x1.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4x1.ifcplane' in typeof(BasisSurface)))) or ('ifc4x1.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1)) to (('ifc4x2.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4x2.ifcplane' in typeof(BasisSurface)))) or ('ifc4x2.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1))

IFC4X3_RC3

modificationswhere_rules UsenseCompatible definitionChanged from (('ifc4x2.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4x2.ifcplane' in typeof(BasisSurface)))) or ('ifc4x2.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1)) to (('ifc4x3_rc3.ifcelementarysurface' in typeof(BasisSurface)) and (not('ifc4x3_rc3.ifcplane' in typeof(BasisSurface)))) or ('ifc4x3_rc3.ifcsurfaceofrevolution' in typeof(BasisSurface)) or (Usense = (U2>U1))

8.9.3.58.1 Semantic definitions at the entity

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.

NOTE  Definition according to ISO/CD 10303-42:1992
The trimmed surface is a simple bounded surface in which the boundaries are the constant parametric lines u~1~ = u1, u~2~ = u2, v~1~ = v1 and v~2~ = v2. All these values shall be within the parametric range of the referenced surface. Cyclic properties of the parameter range are assumed. The rectangular trimmed surface inherits its parameterization directly from the basis surface and has parameter ranges from 0 to |u~2~ - u~1~| and 0 to|v~2~-v~1~|.

NOTE  If the surface is closed in a given parametric direction, the values of u~2~ or v~2~ may require to be increased by the cyclic range.

EXAMPLE  370 degrees is equivalent to 10 degrees, for those surfaces whose parametric form is defined using circular functions (sine and cosine).

NOTE  Entity adapted from rectangular_trimmed_surface in ISO 10303-42.

HISTORY  New entity in IFC2x.

Informal Propositions:

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

8.9.3.58.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment 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.

> IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
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.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcSurface
Dim INVALID The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.

> IFC4 CHANGE Derived attribute promoted from subtypes.
IfcBoundedSurface
IfcRectangularTrimmedSurface
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.

8.9.3.58.2 Entity inheritance

dot_inheritance IfcRectangularTrimmedSurface IfcRectangularTrimmedSurface IfcBoundedSurface IfcBoundedSurface IfcRectangularTrimmedSurface->IfcBoundedSurface IfcBoundedSurface_children 3 more... IfcBoundedSurface_children->IfcBoundedSurface IfcSurface IfcSurface IfcBoundedSurface->IfcSurface IfcSurface_children 3 more... IfcSurface_children->IfcSurface IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcSurface->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.58.3 Formal representations

ENTITY IfcRectangularTrimmedSurface
 SUBTYPE OF (IfcBoundedSurface);
	BasisSurface : IfcSurface;
	U1 : IfcParameterValue;
	V1 : IfcParameterValue;
	U2 : IfcParameterValue;
	V2 : IfcParameterValue;
	Usense : IfcBoolean;
	Vsense : IfcBoolean;
 WHERE
	U1AndU2Different : U1 <> U2;
	V1AndV2Different : V1 <> V2;
	UsenseCompatible : (('IFC4X3_DEV.IFCELEMENTARYSURFACE' IN TYPEOF(BasisSurface)) AND
         (NOT ('IFC4X3_DEV.IFCPLANE' IN TYPEOF(BasisSurface)))) OR
         ('IFC4X3_DEV.IFCSURFACEOFREVOLUTION' IN TYPEOF(BasisSurface)) OR
         (Usense = (U2 > U1));
	VsenseCompatible : Vsense = (V2 > V1);
END_ENTITY;