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IFCGEOMETRICMODELRESOURCE

The data model consists of the following:
18  Entities
Select types
Enumerations

The schema IfcGeometricModelResource defines the resources used for geometric model representations. The primary application of this resource is for 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 IfcGeometricModelResource refers to the clause 6, "Geometric Model" of the standard. The reference is ISO/IS 10303-42:1994, pp. 166. 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 a adaptation process, characterized by:

The geometric 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 buildingSMART International Limited.

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 is within the scope of the geometric model representation in the current version of the geometric model resource:

Fundamental Concepts and Assumptions

NOTE: The following fundamental concepts and assumptions are taken from ISO/CD 10303-42:1992. Please refer to ISO/IS 10303-42:1994, p. 166-167 for the final definition of the formal standard.
NOTE: Only the parts relevant to the subset of ISO 10303-42 (which had been incorporated into the IfcGeometricModelResource) are quoted.

The constructive solid geometry models are represented by teir component primitives and the sequence of Boolean operations (union, intersection, or difference) used in their construction. The entity which communicates the logical sequence of Boolean operations is the boolean_result (IfcBooleanResult) which identifies an operator and two operands. Since the operands can themselves be Boolean results thus enabling nested operations. Swept solids and half-space solids are permissable Boolean operands. The swept solids are the solid of revolution and the solid of linear extrusion. The swept solids are obtained by extruding or sweeping a planar face which may contain holes. The half space solid is essentially defined as a semi-infinite solid on one side of a surface; it may be limited by a box domain.

B-rep models are represented by the set of shells defining the exterior or interior boundaries. The facetted B-rep is restricted to represent B-reps in which all faces are planar and every loop is a poly loop. For such a solid this entity provides a more efficient form of representation. The shell based surface model, the face based surface model and the geometric set entities do not enforce the integrity checks of the manifold solid brep and can be used for the communication of incomplete models (including two-dimensional models).

Interfaced schemas (4):

REFERENCE FROM IFCGEOMETRYRESOURCE
( IfcDimensionCount,
IfcGeometricRepresentationItem,
IfcSurface,
IfcCartesianPoint,
IfcDirection,
IfcAxis1Placement,
IfcLine,
IfcCircle,
IfcVectorSum,
IfcAxis2Placement3D,
IfcCompositeCurve,
Ifc2DCompositeCurve,
IfcPolyline,
IfcTrimmedCurve,
IfcPlane,
IfcCurve,
IfcPoint,
IfcVector,
IfcDotProduct);
REFERENCE FROM IFCMEASURERESOURCE
( IfcPositiveLengthMeasure,
IfcPlaneAngleMeasure);
REFERENCE FROM IFCPROFILERESOURCE
( IfcCircleProfileDef,
IfcRectangleProfileDef,
IfcTrapeziumProfileDef,
IfcEllipseProfileDef,
IfcRoundedRectangleProfileDef,
IfcProfileDef,
IfcProfileTypeEnum);
REFERENCE FROM IFCTOPOLOGYRESOURCE
( IfcClosedShell,
IfcConnectedFaceSet,
IfcShell);

Entities (18):

Go to Diagram 1 IfcBooleanClippingResult
Go to Diagram 1 IfcBooleanResult
Go to Diagram 2 IfcBoundingBox
Go to Diagram 2 IfcBoxedHalfSpace
Go to Diagram 1 IfcCsgSolid
Go to Diagram 3 IfcExtrudedAreaSolid
Go to Diagram 5 IfcFaceBasedSurfaceModel
Go to Diagram 4 IfcFacetedBrep
Go to Diagram 4 IfcFacetedBrepWithVoids
Go to Diagram 5 IfcGeometricSet
Go to Diagram 2 IfcHalfSpaceSolid
Go to Diagram 4 IfcManifoldSolidBrep
Go to Diagram 2 IfcPolygonalBoundedHalfSpace
Go to Diagram 3 IfcRevolvedAreaSolid
Go to Diagram 4 IfcSectionedSpine
Go to Diagram 5 IfcShellBasedSurfaceModel
Go to Diagram 3 IfcSolidModel
Go to Diagram 3 IfcSweptAreaSolid

Select types (3):

Go to Diagram 1 IfcBooleanOperand
Go to Diagram 1 IfcCsgSelect
Go to Diagram 5 IfcGeometricSetSelect

Enumerations (1):

Go to Diagram 1 IfcBooleanOperator