A ramp is a vertical passageway which provides a human or vehicle circulation link between one floor level and another floor level at a different elevation. It can include a landing as an intermediate floor slab. A ramp normally does not include steps. 

The IfcRamp can either be represented:

• as a ramp assembly that aggregates all parts(ramp flight, landing, etc.) with own shape representations
• as a single ramp without decomposition including all shape representations directly at the ramp entity

The walking line is represented by a two-dimensional open curve as the axis. The curve is directed into the upward direction (direction has to be interpreted as specified at the subtypes of IfcCurve). 

If the IfcRamp has no components defined (empty set of SELFIfcProduct.IsDecomposedBy) then the IfcRamp 'Body' geometry can be represented by an own IfcShapeRepresentation. 

If the IfcRamp has components (referenced by SELFIfcProduct.IsDecomposedBy) then no independent 'Body' geometric representation is defined for the IfcRamp. The IfcRamp is then geometrically represented by the geometric representation of its components. The image below illustrates IfcRamp defining the local placement for all components. 

This concept can be applied to the following resources:

• IfcRampFlight - Ramps can be decomposed into ramp flights
• IfcSlab - Ramps can be decomposed into ramp landing, represented by IfcSlab.PredefinedType=LANDING
• IfcRailing - Ramps can be decomposed into railings

The material of the IfcRamp is defined by the IfcMaterial and attached by the IfcRelAssociatesMaterial.RelatingMaterial. It is accessible by the inverse HasAssociations relationship. Material information can also be specified at the IfcRampType, defining the common attribute data for all occurrences of the same type. It is then accessible by the inverse IsDefinedBy relationship pointing to IfcRampType.HasAssociations and via IfcRelAssociatesMaterial.RelatingMaterial to IfcMaterial. If both are specified, then the material directly assigned to IfcRamp overrides the material assigned to IfcRampType. 

This concept can be applied to the following resources:

• IfcRampType

The following restriction can be imposed by view definitions or implementer agreements:

• If the IfcRamp establishes an aggregate, then all contained elements are placed relative to the IfcRamp.ObjectPlacement

This concept can be applied to the following resources:

• Pset_ConcreteElementGeneral
• Pset_PrecastConcreteElementFabrication
• Pset_PrecastConcreteElementGeneral
• Pset_RampCommon

The IfcRamp, as any subtype of IfcBuildingElement, can participate alternatively in one of the two different containment relationships:

• the Spatial Containment (defined here)
• the Element Composition

changes 

• IFC4 changes:
  • Name of the ShapeType attribute changed to PredefinedType
  • Attribute ShapeType made optional