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IfcCShapeProfileDef

Definition from IAI: The IfcCShapeProfileDef defines a section profile that provides the defining parameters of a C-shaped section to be used by the swept area solid. This section is typically produced by cold forming steel. Its parameters and orientation relative to the position coordinate system are according to the following illustration.The centre of the position coordinate system is in the profiles centre of the gravity bounding box.

The centre of gravity, if given, is located in y direction within the center of the bounding box, and in x-direction along the negative x axis, the offset value is given by the offset parameter CentreOfGravityInX.

HISTORY  New entity in Release IFC2x Edition 2.
IFC2x Edition 3 CHANGE  All profile origins are now in the center of the bounding box. The attribute CentreOfGravityInX has been made OPTIONAL. Upward compatibility for file based exchange is guaranteed.

Illustration:

C-shape profile

Position
The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of:

  • IfcSweptAreaSolid.Position
by using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (e.g. upper-left bound).

Parameter
The parameterized profile is defined by a set of parameter attributes, see attribute definition below.

Table: Parameters of C-shape profile definition

EXPRESS specification:

ENTITY IfcCShapeProfileDef
SUBTYPE OF ( IfcParameterizedProfileDef);
Depth  :  IfcPositiveLengthMeasure;
Width  :  IfcPositiveLengthMeasure;
WallThickness  :  IfcPositiveLengthMeasure;
Girth  :  IfcPositiveLengthMeasure;
InternalFilletRadius  :  OPTIONAL IfcPositiveLengthMeasure;
CentreOfGravityInX  :  OPTIONAL IfcPositiveLengthMeasure;
WHERE
WR1  :  Girth < (Depth / 2.);
WR2  :  NOT(EXISTS(InternalFilletRadius)) OR ((InternalFilletRadius <= Width/2.) AND (InternalFilletRadius <= Depth/2.));
WR3  :  (WallThickness < Width/2.) AND (WallThickness < Depth/2.);
END_ENTITY;

Attribute definitions:

Depth  :  Profile depth, see illustration above (= h).
Width  :  Profile width, see illustration above (= b).
WallThickness  :  Constant wall thickness of profile (= ts).
Girth  :  Lengths of girth, see illustration above (= c).
InternalFilletRadius  :  Internal fillet radius according the above illustration (= r1). If it is not given, zero is assumed.
CentreOfGravityInX  :  Location of centre of gravity along the x axis measured from the center of the bounding box.
IFC2x Edition 2 Addendum 2 CHANGE The attribute CentreOfGravityInX has been made optional. Upward compatibility for file based exchange is guaranteed.

Formal Propositions:

WR1  :  The girth shall be smaller than half of the depth.
WR2  :  If the value for InternalFilletRadius is given, it shall be smaller than half of the Depth and half of the Width.
WR3  :  The WallThickness shall be smaller than half of the Width and half of the Depth.

Inheritance graph

ENTITY IfcCShapeProfileDef;
ENTITY IfcProfileDef;
ProfileType  :  IfcProfileTypeEnum;
ProfileName  :  OPTIONAL IfcLabel;
ENTITY IfcParameterizedProfileDef;
Position  :  IfcAxis2Placement2D;
ENTITY IfcCShapeProfileDef;
Depth  :  IfcPositiveLengthMeasure;
Width  :  IfcPositiveLengthMeasure;
WallThickness  :  IfcPositiveLengthMeasure;
Girth  :  IfcPositiveLengthMeasure;
InternalFilletRadius  :  OPTIONAL IfcPositiveLengthMeasure;
CentreOfGravityInX  :  OPTIONAL IfcPositiveLengthMeasure;
END_ENTITY;