Definition from IAI: This class defines elements of a distribution system that facilitate the distribution of energy or matter, such as air, water or power.
The following parameters shall be given:
- Height, taken from the BoundingBox definition, provides the height of the profile definition.
- Width, taken from the BoundingBox definition, provides the width of the profile definition.
- Length, taken from the BoundingBox definition, provides the depth of the extrusion.
HISTORY: New entity in IFC R2.0.
ISSUES: See issues and change log for changes made in IFC R2x.
Geometry Use Definitions
The geometric representation of IfcDistributionFlowElement is given by the IfcProductDefinitionShape, allowing multiple geometric representations. Included are:
Local Placement
The local placement is defined in the supertype IfcProduct. It is defined by a subtype of IfcObjectPlacement which can define an absolute placement, relative placement, or grid reference, with each defining the local coordinate system referenced by all geometric representations. The PlacementRelTo relationship of IfcLocalPlacement, if given, shall point to the same IfcSpatialStructureElement which is used in the ContainedInStructure inverse attribute, or to a referenced spatial structure element at a higher level. If the relative placement is not used, the absolute placement is defined within the world coordinate system.
Informal propositions for local placement:
- If the LocalPlacement is specified, then all aggregated components should use this placement as their relative placement.
Geometric Representation
The standard geometric representation of IfcDistributionFlowElement is defined using the following multiple shape representations for its definition:
- Axial: A two-dimensional open curve (IfcBoundedCurve) defining the axis for the distribution flow element.
- Body: A Swept Solid Representation or a CSG representation defining the 3D shape of the distribution flow element.
- B-Rep Representation: The faceted B-Rep capabilities (with or without voids) shall be supported for B-Rep representation.
First representation: Axial
The distribution flow element axis is represented by a two-dimensional open curve within a particular shape representation. The distribution flow element axis is used to apply the length parameter to the distribution flow element geometry. The following attribute values shall be used
IfcShapeRepresentation
- RepresentationIdentifier : 'Axial'
- RepresentationType : 'GeometricSet'
 |
The distribution flow element shall include a single geometric representation item of type IfcPolyline. |
Second representation: Body
The body of the IfcDistributionFlowElement is defined by using:
- SweptSolid representation for distribution flow elements without clippings.
- CSG representation for distribution flow elements with clippings.
IfcShapeRepresentation
- RepresentationIdentifier : 'DistributionFlowElementsBody'
- RepresentationType : 'SweptSolid' or 'CSG'
SweptSolid representation
The standard geometric representation (for body) of IfcDistributionFlowElement is defined using the swept solid representation. The following additional constraints apply to the swept solid representation:
- Solid: IfcExtrudedAreaSolid is required,
- Profile: IfcArbitraryProfileDef shall be supported.
- Extrusion: The profile shall be extruded vertically, i.e., in the direction of the z-axis of the coordinate system of the referred spatial structure element. It might be further constrained to be in the direction of the global z-axis in implementers agreements. The extrusion axis shall be perpendicular to the swept profile, i.e. pointing into the direction of the z-axis of the Position of the IfcExtrudedAreaSolid.
| The profile of a distribution flow element is described in the ground view and extruded vertically. The profile (also identical with the foot print of the distribution flow element) is defined by the IfcArbitraryProfileDef (excluding its subtypes). The distribution flow element has a single unchanged width and height. |
CSG representation
The advanced geometric representation (for body) of IfcFlowSegment is defined using the CSG representation. The following additional constraints apply to the swept solid representation:
- Solid: see standard geometric representation
- Profile: see standard geometric representation
- Extrusion: see standard geometric representation
- Boolean result: The IfcBooleanClippingResult shall be supported, allowing for Boolean differences between the swept solid (here IfcExtrudedAreaSolid) and one or several IfcHalfSpaceSolid.