 | Alignment Curve 2D Horizontal |
| Item | SPF | XML | Change | Description | IFC4x3_RC1 to IFC4x3_RC2 |
|---|---|---|---|---|
| IfcAlignmentHorizontal | MODIFIED | Schema changed from IFCGEOMETRICCONSTRAINTRESOURCE to IFCPRODUCTEXTENSION. Name changed from IfcAlignment2DHorizontal to IfcAlignmentHorizontal. | ||
| GlobalId | X | X | MODIFIED | Name changed from StartDistAlong to GlobalId. Type changed from IfcLengthMeasure to IfcGloballyUniqueId. Instantiation changed from OPTIONAL. |
| OwnerHistory | X | X | MODIFIED | Name changed from Segments to OwnerHistory. Type changed from IfcAlignment2DHorizontalSegment to IfcOwnerHistory. Instantiation changed to OPTIONAL. Aggregation changed from LIST to NONE. Xsdformat changed from Default to Attribute. |
| Name | ADDED | |||
| Description | ADDED | |||
| ObjectType | ADDED | |||
| ObjectPlacement | ADDED | |||
| Representation | ADDED | |||
| StartDistAlong | ADDED | |||
| Segments | ADDED | |||
| HasAssignments | ADDED | |||
| Nests | ADDED | |||
| IsNestedBy | ADDED | |||
| HasContext | ADDED | |||
| IsDecomposedBy | ADDED | |||
| Decomposes | ADDED | |||
| HasAssociations | ADDED | |||
| IsDeclaredBy | ADDED | |||
| Declares | ADDED | |||
| IsTypedBy | ADDED | |||
| IsDefinedBy | ADDED | |||
| ReferencedBy | ADDED | |||
| PositionedRelativeTo | ADDED | |||
| ReferencedInStructures | ADDED | |||
| LayerAssignment | DELETED | |||
| StyledByItem | DELETED | |||
| ToAlignmentCurve | DELETED | IFC4x3_RC2 to IFC4x3_RC3 | ||
| IfcAlignmentHorizontal | ||||
| Segments | X | DELETED |
An IfcAlignmentHorizontal is a linear reference projected onto the horizontal x/y plane. Points along a horizontal alignment have two coordinate values, x and y in the local Cartesian engineering system.
The horizontal alignment is defined by segments that are connected end-to-start. The transition at the segment connection is not enforced to be tangential, if the “tangential continuity” flag is set to false, otherwise a tangential continuity shall be preserved. Based on the context of the project, they are geo-referenced and convertible into Northing and Easting values.
NOTE Georeferencing is provided by IfcMapConversion through the IfcGeometricRepresentationContext defined at IfcProject.
| # | Attribute | Type | Cardinality | Description | G |
|---|---|---|---|---|---|
| IfcRoot | |||||
| 1 | GlobalId | IfcGloballyUniqueId | Assignment of a globally unique identifier within the entire software world. | X | |
| 2 | OwnerHistory | IfcOwnerHistory | ? |
Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object,
NOTE only the last modification in stored - either as addition, deletion or modification. IFC4 CHANGE The attribute has been changed to be OPTIONAL. | X |
| 3 | Name | IfcLabel | ? | Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule. | X |
| 4 | Description | IfcText | ? | Optional description, provided for exchanging informative comments. | X |
| IfcObjectDefinition | |||||
| HasAssignments | IfcRelAssigns @RelatedObjects | S[0:?] | Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups. | X | |
| Nests | IfcRelNests @RelatedObjects | S[0:1] | References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition. | X | |
| IsNestedBy | IfcRelNests @RelatingObject | S[0:?] | References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).
IFC4 CHANGE The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition. | X | |
| HasContext | IfcRelDeclares @RelatedDefinitions | S[0:1] | References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.
IFC4 CHANGE The inverse attribute datatype has been added. | X | |
| IsDecomposedBy | IfcRelAggregates @RelatingObject | S[0:?] | References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| Decomposes | IfcRelAggregates @RelatedObjects | S[0:1] | References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).
IFC4 CHANGE The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates. | X | |
| HasAssociations | IfcRelAssociates @RelatedObjects | S[0:?] | Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification. | X | |
| IfcObject | |||||
| 5 | ObjectType | IfcLabel | ? | The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED. | X |
| IsDeclaredBy | IfcRelDefinesByObject @RelatedObjects | S[0:1] | Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| Declares | IfcRelDefinesByObject @RelatingObject | S[0:?] | Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE New inverse relationship, change made with upward compatibility for file based exchange. | X | |
| IsTypedBy | IfcRelDefinesByType @RelatedObjects | S[0:1] | Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.
IFC4 CHANGE New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange. | X | |
| IsDefinedBy | IfcRelDefinesByProperties @RelatedObjects | S[0:?] | Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.
IFC4 CHANGE The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange. | X | |
| IfcProduct | |||||
| 6 | ObjectPlacement | IfcObjectPlacement | ? | Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system. | X |
| 7 | Representation | IfcProductRepresentation | ? | Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement. | X |
| ReferencedBy | IfcRelAssignsToProduct @RelatingProduct | S[0:?] | Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product. | X | |
| PositionedRelativeTo | IfcRelPositions @RelatedProducts | S[0:?] | X | ||
| ReferencedInStructures | IfcRelReferencedInSpatialStructure @RelatedElements | S[0:?] | X | ||
| IfcLinearElement | |||||
| IfcAlignmentHorizontal | |||||
Alignment Horizontal Attributes
The Alignment Horizontal Attributes concept template applies to this entity as shown in Table 44.
Table 44 — IfcAlignmentHorizontal Alignment Horizontal Attributes |
Instance diagram
<?xml version="1.0" encoding="utf-8"?>
<ConceptRoot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" uuid="a4a31de4-7137-4121-a6da-8e9adec1399e" name="IfcAlignmentHorizontal" applicableRootEntity="IfcAlignmentHorizontal">
<Applicability>
<Template ref="98a8569d-942a-4a37-88b8-5ed70956158f" />
<TemplateRules operator="and">
</TemplateRules>
</Applicability>
<Concepts>
<Concept uuid="6cb7d56f-9813-47b3-8cd7-d14c504d2afd" name="Alignment Horizontal Attributes">
<Template ref="9abb858d-493a-4ce1-9a40-9ae26c74dcc8" />
<TemplateRules operator="and">
<TemplateRule />
</TemplateRules>
</Concept>
</Concepts>
</ConceptRoot>
<xs:element name="IfcAlignmentHorizontal" type="ifc:IfcAlignmentHorizontal" substitutionGroup="ifc:IfcLinearElement" nillable="true"/>
<xs:complexType name="IfcAlignmentHorizontal">
<xs:complexContent>
<xs:extension base="ifc:IfcLinearElement"/>
</xs:complexContent>
</xs:complexType>
ENTITY IfcAlignmentHorizontal
SUBTYPE OF (IfcLinearElement);
END_ENTITY;
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