IfcEdgeCurve
Definition from ISO/CD 10303-42:1992: An edge curve is a special
subtype of edge which has its geometry fully defined. The geometry is defined
by associating the edge with a curve which may be unbounded. As the topological
and geometric directions may be opposed, an indicator (same sense) is used to
identify whether the edge and curve directions agree or are opposed. The
Boolean value indicates whether the curve direction agrees with (TRUE) or is in
the opposite direction (FALSE) to the edge direction. Any geometry associated
with the vertices of the edge shall be consistent with the edge geometry.
NOTE: Corresponding STEP entity:
edge_curve. Please refer to ISO/IS 10303-42:1994, p. 132 for the final
definition of the formal standard. Due to the general IFC model specification
rule not to use multiple inheritance, the subtype relationship to
geometric_representation_item is not included.
HISTORY: New Entity in IFC Release
2.x.
Informal propositions:
- The domain of the edge curve is formally defined to be the domain of
its edge geometry as trimmed by the vertices. This domain does not include the
vertices.
- An edge curve has non-zero finite extent.
- An edge curve is a manifold.
- An edge curve is arcwise connected.
- The edge start is not a part of the edge domain.
- The edge end is not a part of the edge domain.
- Vertex geometry shall be consistent with edge geometry.
EXPRESS specification:
Attribute definitions:
| EdgeGeometry
|
:
|
The curve which defines the shape and spatial location of the edge. This curve may be unbounded and is
implicitly trimmed by the vertices of the edge; this defines the edge domain. Multiple edges can reference
the same curve.
|
| SameSense
|
:
|
This logical flag indicates whether (TRUE), or not (FALSE) the senses of the edge and the curve defining
the edge geometry are the same. The sense of an edge is from the edge start vertex to the edge end vertex;
the sense of a curve is in the direction of increasing parameter.
|
Inheritance graph