8.9 IfcGeometryResource

8.9.1 Schema definition

The schema IfcGeometryResource defines the resources used for geometric representations. The primary application of this resource is for representation of the shape or geometric form of an element. The geometric representation items defined here are also used to describe geometric models within the schema IfcGeometricModelResource.

The following is within the scope of the geometry resource:

definition of points directly by their coordinate values and by parameter values on curves and surfaces
definition of directions, vectors, and axis placements
definition of transformation operators, both uniform and non-uniform
definition of parametric curves
definition of conic curves
definition of curves defined on a parametric surface
definition of offset curves
definition of elementary surfaces
definition of swept surfaces
definition of parametric spline curves and surfaces
definition of mapped items mapping source representations using transformation operators

NOTE Definition according to ISO 10303-42 Curves The curve entities include lines, some elementary conics, and some referentially or procedurally defined curves. All the curves have a well defined parameterization which makes it possible to trim a curve or identify points on the curve by parameter value. For the conic curves a method of representation is used which separates their geometric form from their orientation and position in space. In each case, the position and orientation information is conveyed by an axis2 placement. A composite curve entity, which includes the facility to communicate continuity information at the curve-to-curve transition points, is provided for the construction of more complex curves. The offset curve type is a curve defined with reference to other geometry. Separate offset curves entities exist for 2D and 3D applications.

8.9 IfcGeometryResource

8.9.1 Schema definition

8.9.2 Types

8.9.3 Entities

8.9.4 Property Sets

8.9.5 Quantity Sets

8.9.6 Functions

8.9.7 Rules

8.9.8 PropertyEnumerations