22.214.171.124.1 Semantic definition
The cylindrical surface is a surface unbounded in the direction of z. Bounded cylindrical surfaces are defined by using a subtype of IfcBoundedSurface with BasisSurface being a cylindrical surface.
The inherited attributes are interpreted as
- SELF\IfcElementarySurface.Position defines the location and orientation of the cylindrical surface.
- SELF\IfcElementarySurface.Position.Location defines a point on the axis of the cylindrical surface.
- SELF\IfcElementarySurface.Position.P defines the direction of the axis of the cylindrical surface.
C = Position.Location x = Position.P y = Position.P z = Position.P R = Radiusand the surface is parameterized as:
In the above parameterization the length unit for the unit vectors z is equal to that of the radius R. In the placement coordinate system defined above, the surface is represented by the equation S = 0, where
The direction of the normal is away from the axis of the cylinder.
126.96.36.199.2 Entity inheritance
|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.
This attribute is formally derived.
The space dimensionality of IfcSurface. It is always a three-dimensional geometric representation item.
The position and orientation of the surface. This attribute is used in the definition of the parameterization of the surface.
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The radius of the cylindrical surface.
188.8.131.52.4 Formal representation
ENTITY IfcCylindricalSurface SUBTYPE OF (IfcElementarySurface); Radius : IfcPositiveLengthMeasure; END_ENTITY;