8.9.2.4 IfcBSplineSurfaceForm
8.9.2.4.1 Semantic definition
The IfcBSplineSurfaceForm represents a part of a surface of some specific form.
8.9.2.4.2 Type values
| Type | Description |
|---|---|
CONICAL_SURF
|
A bounded portion of the surface of a right circular cone. |
CYLINDRICAL_SURF
|
A bounded portion of a cylindrical surface. |
GENERALISED_CONE
|
A special case of a ruled surface in which the second curve degenerates to a single point; when represented by a B-spline surface all the control points along one edge will be coincident. |
PLANE_SURF
|
A bounded portion of a plane represented by a B-spline surface of degree 1 in each parameter. |
QUADRIC_SURF
|
A bounded portion of one of the class of surfaces of degree 2 in the variables x, y and z. |
RULED_SURF
|
A surface constructed from two parametric curves by joining with straight lines corresponding points with the same parameter value on each of the curves. |
SPHERICAL_SURF
|
A bounded portion of a sphere, or a complete sphere, represented by a B-spline surface. |
SURF_OF_LINEAR_EXTRUSION
|
A bounded portion of a surface of linear extrusion represented by a B-spline surface of degree 1 in one of the parameters. |
SURF_OF_REVOLUTION
|
A bounded portion of a surface of revolution. |
TOROIDAL_SURF
|
A torus, or portion of a torus, represented by a B-spline surface. |
UNSPECIFIED
|
A surface for which no particular form is specified. |
8.9.2.4.3 Formal representation
TYPE IfcBSplineSurfaceForm = ENUMERATION OF
(CONICAL_SURF
,CYLINDRICAL_SURF
,GENERALISED_CONE
,PLANE_SURF
,QUADRIC_SURF
,RULED_SURF
,SPHERICAL_SURF
,SURF_OF_LINEAR_EXTRUSION
,SURF_OF_REVOLUTION
,TOROIDAL_SURF
,UNSPECIFIED);
END_TYPE;