IfcLShapeProfileDef
Definition
from IAI: The IfcLShapeProfileDef
defines a section profile that provides the defining parameters of an
L-shaped section (equilateral L profiles are also covered by this
entity) to be used by the swept area
solid. Its parameters and orientation relative to the position
coordinate system are according to the following illustration. The
shorter leg has the same direction as the positive x-axis, the longer
or equal leg the same as the positive y-axis. 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 x direction
along the negative x axis, the offset
value is given by the offset parameter CentreOfGravityInX,
and in y-direction along the negative y axis, the offset value is given
by the offset parameter CentreOfGravityInY.
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 CentreOfGravityInY
has been made OPTIONAL. Upward compatibility for file based exchange is
guaranteed.
Illustration:
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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.
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Note:
The black coordinate axes show the
underlying coordinate system of the swept surface or swept area solid |
Position
The profile is inserted into the underlying
coordinate system of the swept area solid by using the Position
attribute. In this example (cardinal point of gravity) the
attribute values of IfcAxis2Placement2D
are:
Location
=
IfcCartesianPoint(<CentreOfGravityInX>,<CentreOfGravityInY>)
RefDirection = NIL (defaults to 1.,0.)
Note: if the values of CentreOfGravityInX
and CentreOfGravityInY
are given, they are already negative
values, since the shift of the centre of gravity is into the negative X
and negative Y axis.
Parameter
If the Width
parameter is not given, it defaults to the value
of Depth, therefore an equal sided L-shape profile is created, if the LegSlope
parameter is not given, both legs have parallel edges.
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Table:
Parameters of equal-sided and non-equal sided L-shaped
section
definition
EXPRESS specification:
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| WR21
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:
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Thickness < Depth;
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| WR22
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:
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NOT(EXISTS(Width)) OR (Thickness < Width);
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Attribute definitions:
| Depth
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:
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Leg length, see illustration above (= h).
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| Width
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:
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Leg length, see illustration above (= b). If not given, the value of the Depth attribute is applied to
Width.
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| Thickness
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:
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Constant wall thickness of profile, see illustration above (= ts).
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| FilletRadius
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Fillet radius according the above illustration (= r1). If it is not given, zero is assumed.
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| EdgeRadius
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:
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Edge radius according the above illustration (= r2). If it is not given, zero is assumed.
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| LegSlope
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:
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Slope of leg of the profile. If it is not given, zero is assumed.
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| CentreOfGravityInX
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:
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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.
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| CentreOfGravityInY
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:
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Location of centre of gravity along the Y axis measured from the center of the bounding box.
IFC2x Edition 2 Addendum 2 CHANGE The attribute CentreOfGravityInY has been made optional. Upward compatibility for file based exchange is guaranteed.
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Formal Propositions:
| WR21
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:
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The thickness of the flange has to be smaller than the depth of the profile.
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| WR22
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:
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The thickness of the flange has to be smaller than the width of the profile (if given).
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Inheritance graph
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| ENTITY IfcLShapeProfileDef;
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