IFCTOPOLOGYRESOURCE
The data model consists of the following:
The schema IfcTopologyResource defines the resources used for
topological representations. The primary application of this resource is its
use in the Boundary representation of the shape or geometric form of a product
model.
NOTE: The definitions of this resource of
the IFC model have been taken from the Integrated Resource, part 42 "Integrated
generic resources: Geometric and topological representations" of the ISO
standard 10303: "Industrial automation systems and integration - Product data
representation and exchange". The IfcTopologyResource refers to the clause 5,
"Topology" of the standard. The reference is ISO/IS 10303-42:1994, pp. 122. The
improved definitions of the second edition, ISO/DIS 10303-42:1999 have been
used, when applicable.
The definitions taken from ISO/IS 10303-42:1994 have undergone an
adaptation process, characterized by:
- adaptation of the IFC naming convention (inner majuscules and Ifc
prefix)
- adaptation of the STEP entities, where multiple inheritance or
non-exclusive inheritance (i.e. AND or ANDOR subtype constraints) are used
- selection of a subset of the IR, using subtype and select
pruning
- omission of the name attribute at the representation item
The topological representation of the shape is defined following the
adaptation of the ISO/CD 10303-42:1992, Industrial Automation Systems
and Integration: Product Data Representation and Exchange - Part 42: Integrated
Generic Resources. Geometric and Topological Representation. The type,
class, and function semantic definition sections follow the adapted wording of
the working draft, which is clearly indicated and quoted at each reference. The
definitions on geometric and topological representation (when taken from ISO/CD
10303-42:1992) are explicitly excluded from the copyright of the International
Alliance of Interoperability.
For more information on the definitions
as defined in the formal ISO standard please refer to: ISO/IS 10303-42:1994,
Industrial Automation Systems and Integration: Product Data Representation and
Exchange - Part 42: Integrated Generic Resources. Geometric and Topological
Representation. The formal standard can be obtained through the local
publishers of standards in each individual country.
The following are within the scope of the topology schema:
- definition of the fundamental topological entities vertex, edge, and
face, each with a specialized subtype to enable it to be associated with the
geometry of a point, curve, or surface, respectively;
- collections of the basic entities to form topological structures of
path, loop and shell and constraints to ensure the integrity of these
structures;
- orientation of topological entities.
Interfaced schemas (2):
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IfcCartesianPoint,
IfcPoint,
IfcCurve,
IfcLine,
IfcPolyline,
IfcTrimmedCurve,
IfcCompositeCurve,
IfcAxis2Placement2D,
IfcAxis2Placement3D,
IfcRepresentationItem,
IfcCircle,
IfcEllipse,
IfcSurface,
IfcPlane,
IfcCurveBoundedPlane,
IfcBezierCurve);
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Entities (19):
Select types (1):
Functions (3):
