Index Page
EXPRESS Definition |
EXPRESS-G Diagram |
IDL Definition |
The schema IfcKernel defines the most abstract part within the IFC architecture. It captures general constructs, that are basically founded by their different semantic meaning in common understanding of object orientation, like object and relationship. Those are then specialized into non-AEC/FM specific constructs, like product and process which form the main entry points for the next level, the Core Extension layer.
The IfcKernel utilizes the translation of the IFC Meta model into IFC object model specification. It handles the basic functionality, such as relative location of products in space, sequence of processes in time, or general purpose grouping mechanism. It also lays the foundation of extensibility of IFC model by providing type driven property definition and property definition extension.
The specification of IfcKernel is not intended for independent implementation, however, all shared and domain models at lower levels within the IFC architecture are required to use the kernel definitions to root their definitions.
EXPRESS Definition
Definition from IAI: This enumeration defines the different containment types, that further refine the containment relationship.
Enumeration:
ProjectContainer |
|
SiteContainer |
|
BuildingContainer |
|
BuildingStoreyContainer |
|
SpaceContainer |
|
NOTE This type is new in IFC Release 1.5
ISSUE: See Issues I-114 and I-116 for changes made in IFC Release 1.5.
EXPRESS Definition
Definition from IAI: The IfcProxyTypeEnum defines the high level categorization of an IfcProxy. It indicates to which subtype of IfcObject the Proxy would otherwise comply.
Enumeration:
Product |
|
Process |
|
Control |
|
Document |
|
Resource |
|
NOTE This type is new in IFC Release 1.5
ISSUE: See issue I-184 for changes made in IFC Release 1.5.
EXPRESS Definition
Definition from IAI: This enumeration defines the available Generic Types for IfcResource.
Enumeration:
Labor |
|
Equipment |
|
Material |
|
NOTE This type is new in IFC Release 1.5.1
ISSUE: See issue I-324 for changes made in IFC Release 1.5.1.
EXPRESS Definition
Definition from IAI: The IfcSequenceTypeEnum defines the different ways, in which a time lag is applied to a sequence between two processes.
Enumeration:
Start_Start |
|
Start_Finish |
|
Finish_Start |
|
Finish_Finish |
|
NOTE This type is new in IFC Release 1.5
ISSUE: See issue I-200 for changes made in IFC Release 1.5.
Type IfcObjectWithPlacementSelect
EXPRESS Definition
Definition from IAI: The IfcObjectWithPlacementSelect defines the three high level classes in IFC, that define their own placement. These objects can therefore provide the local (or in case of IfcProject -- global) coordinate system to which other object coordinate systems can refer.
Select:
IfcProduct |
|
IfcModelingAid |
|
IfcProject |
|
NOTE This type is new in IFC Release 1.5
ISSUE: See issues I-212 and I-312 for changes made in IFC Release 1.5.
EXPRESS Definition
Definition from IAI: The IfcControl is the abstract generalization of all concepts that control or constrain Products or Processes in general. It can be seen as a specification, regulation, constraint or other requirement applied to a product or process whose requirements and provisions must be fulfilled.
Examples for Controls are space programme, construction guides, etc. It is defined in the Kernel but will be reused and specialized in other schemas.
NOTE: This class carries the semantics of IFC Release 1.0 class IfcControlObject.
ISSUE: See issue I-094 for changes made in IFC Release 1.5.
No attributes and no Formal Propositions are defined at this level.
This class is not typed in IFC Release 1.5.1 -- there is no type definition.
EXPRESS Definition
Definition from IAI: The IfcDocument is the abstract generalization of all document type information that belongs to a shared project information. There are two kinds of documents, structured, where document contents are still recognizable, and unstructured, where only the document header is recognized. Further IFC Releases will further define and distinguish document types. Current examples are:
NOTE: New Class in IFC Release 1.5
ISSUE: See issue I-094 for changes made in IFC Release 1.5.
No Attributes and no Formal Propositions are defined at this level.
This class is not typed in IFC Release 1.5.1 -- there is no type definition.
EXPRESS Definition
Definition from IAI: The generalization of any arbitrary group. A group is an aggregation of objects, which do not have any particular positioning relationship. Therefore a group is an aggregation under some non-geometrical/topological grouping aspects. An example for a group is the system, since it groups elements under the aspect of their role, regardless of their position in a building. A group can hold an aggregation of products, processes or other groups. Groups can therefore be nested.
The GroupPurpose attribute may assign a descriptor, that defines the purpose of the group. As an example, a complex of buildings will be generated by assigning the individual buildings through the IfcRelGroups relationship to an IfcGroup, which is further specified by the GroupPurpose descriptor "BuildingComplex". Similarly the site complex is handled by an IfcGroup with the the GroupPurpose descriptor "SiteComplex".
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issues I-088 and I-213 for changes made in IFC Release 1.5.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
OPT |
GroupPurpose |
Description of the Purpose behind grouping. |
STRING |
see type |
see type |
NIL |
INV |
GroupedBy |
Contains the relationship that assigns the group members to the group object. |
see type |
see type |
n/a |
No Formal Propositions are defined at this level.
This class is not typed in IFC Release 1.5.1 -- there is no type definition.
EXPRESS Definition
Definition from IAI: The relative placement between two products. It defines that the related object is placed within the local coordinate system of the relating object. Rules to prevent cyclic relative placements have to be introduced on the application level.
The following conventions shall apply, if relative placement is used:
If the PlacementRelTo Relationship is not given, then it defaults to an absolute placement within the WCS, i.e. relative to the IfcProject.
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issues I-212, I-255, I-260 and I-270 for changes made in IFC Release 1.5.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
OPT |
PlacementRelTo |
Reference to Object that provides the relative placement by its local coordinate system, if it is omitted, then the Local Placement is given to the WCS, established by the IfcProject. |
see type |
see type |
not optional |
|
|
RelativePlacement |
Geometric placement that defines the transformation from the related coordinate system into the relating. The placement can be either 2D or 3D, depending on the dimension count of the coordinate system. |
see type |
see type |
n/a |
No Formal Propositions are defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: An IfcModelingAid provides the general concept for constructs that support the creation of design artifact, in particular its geometric form. They are part of the project information set, but not part of the artifact itself. Most common example of a modeling aid are the local placement and the design grid. Both provide aid to place Products into the design space. The grid supports in addition the definition of elements' constraint location and sometimes form, but the grid is not part of the constructed building.
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issues I-254 and I-255 for changes made in IFC Release 1.5.
No Attributes and no Formal Propositions are defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: The generalization of any semantically treated things and processes within IFC. Examples of IfcObject include physically tangible items, such as wall, beam or covering, physically existing items, such as spaces, or conceptual items, such as grids or virtual boundaries. It also stands for processes, such as work tasks, as well as for controls, documents, etc.
Objects are independent pieces of information that might contain or reference other pieces of information, most notably properties. For properties that are shared among multiple instances of an Object the Type driven Property definitions are used, which are shared by value. For properties whose values vary for each instance of an Object, the Occurrence Properties are defined. Property definitions can be enhanced to deal with specific national, application type, or project requirements; therefore there is a placeholder for Extended Properties.
NOTE: This entity is an enhanced definition of IFC Release 1.0 IfcProjectObject.
ISSUE: See issues I-079, I-085 for changes made in IFC Release 1.5.
See issue I-361 for changes made in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
OwnerHistory |
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. |
see type |
see type |
n/a |
|
|
TypeDefinitions |
Assignment of the Property Type Definition to allow dynamic extension of object definitions, all instantiable subtypes will use Property Type Definition as the preferred way to define properties that are shared by multiple instances of the same object type. The Property Type Definition for the generic type of the object is predefined within the IFC object model specification using definition tables. It now allows for multiple types per IfcObject, each Domain can add its type to the Object, and there can be also cross domain types. |
List[0:?] IfcPropertyTypeDef |
see type |
see type |
empty list |
|
OccurrenceProperties |
List of references to Property Occurrence Definition, that overwrites shared property values within the assigned Property Type Definition. This allows the handling of exceptions for Type Defined Properties. |
List [0:?] IfcOccurrencePropertySet |
see type |
see type |
empty list |
|
ExtendedProperties |
List of references to Property Occurrence Definition that are non type driven. That allows the extension of Property Definition of an object. |
List [0:?] IfcPropertySet |
see type |
see type |
empty list |
INV |
PartOfGroups |
References to the grouping relationships, which allows the object to be part of many groups |
Set [0:?] IfcRelGroups |
see type |
see type |
NIL |
INV |
Nests |
Reference to the nesting relationship, that allows this object to be the nest of other nested objects |
Set [0:1] IfcRelNests |
see type |
see type |
NIL |
INV |
IsNestedBy |
References to the nesting relationship, that allows this object to be nested within other objects |
Set [0:?] IfcRelNests |
see type |
see type |
NIL |
INV |
Contains |
Set of Relationships to other Objects that are contained by this object. |
Set [0:2] IfcRelContains |
see type |
see type |
NIL |
INV |
IsContainedBy |
Set of Relationships to other Objects in which this object is contained. |
Set [0:?] IfcRelContains |
see type |
see type |
NIL |
Formal Propositions:
WR21 |
The IfcPropertySet that is referenced by the ExtendedProperties relationship shall not include type driven attribute set, such as IfcSharedPropertySet and IfcOccurrencePropertySet. |
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: An action taking place in building construction with the intent of acquiring or constructing products. Processes are placed in sequence (including overlapping for parallel tasks) in time.
NOTE: This entity is an enhanced definition of IFC Release 1.0 IfcProductObject.
ISSUE: See issues I-200, I-201 for changes made in IFC Release 1.5.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
PerformedBy |
Reference to a set of actors, which perform the process |
Set [0:?] IfcActorSelect |
see type |
see type |
empty set |
OPT |
Classification |
Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it. |
see type |
see type |
NIL |
|
INV |
IsSuccessorFrom |
Relative placement in time, refers to the previous processes for which this process is successor. |
Set [0:?] IfcRelSequence |
see type |
see type |
NIL |
INV |
IsPredecessorTo |
Relative placement in time, refers to the previous processes for which this process is predecessor. |
Set [0:?] IfcRelSequence |
see type |
see type |
NIL |
INV |
ProcessesProducts |
References to products that are either input or output for the process |
Set [0:2] IfcRelProcessesProducts |
see type |
see type |
NIL |
INV |
UsesResources |
References to resources used in the process |
Set [0:?] IfcRelUsesResource |
see type |
see type |
NIL |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: Any object, manufactured, supplied or created for incorporation into an AEC/FM project. This also includes objects that are created indirectly by other products, as spaces are defined by bounding elements. Products can be designated for permanent use or temporary use, an example for the latter is formwork.
Products are defined by their properties, whereas shape, cost and classification references are provided as direct interfaces at the IfcProduct object. Products occur at a specific location in space. They are placed relatively to other products, ultimately to the IfcSite, by means of the IfcLocalPlacement relationship object.
NOTE: This entity is an enhanced definition of IFC Release 1.0 IfcProductObject
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
LocalPlacement |
Contained relative placement in space, refers to the product that provides the local coordinate system for the Relative Placement and includes the transformation for the object coordinate system. |
see type |
see type |
n/a |
|
OPT |
ProductShape |
Reference to the shape definition of the product. The Product Shape allows for aggregation of Product Component Shapes and therefore for a componentization at the geometric level. It also provides for multiple representations of the Product Shape |
see type |
see type |
NIL |
|
OPT |
ProductCost |
Reference to the cost definition of the product. |
see type |
see type |
NIL |
|
OPT |
Classification |
Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it. |
see type |
see type |
NIL |
|
INV |
ProcessedInProcesses |
Reference to the Processes (via the objectified relationship) in which the Product is used as in- or output. |
Set [0:?] IfcRelProcessesProducts |
see type |
see type |
NIL |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: The undertaking of some engineering activities leading towards a product. It acts as the top container for all objects defining a project. The Project also holds the units used for certain measures throughout the project and the central registry, currently only for team members, applications and materials. The IfcProject establishes the World Coordinate System, WCS.
NOTE: This entity is the same as in IFC Release 1.0, only the unit assignment has been added.
ISSUE: See issues I-084, I-001,
I-003 for changes made in IFC Release 1.5.
See issues I-298, I-328 for changes
made in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
UnitsInContext |
Defines the units of measure that will be referred by defined data types in the attribute values of all attributes and properties of objects and relationships, defined in the context of this project. |
see type |
see type |
n/a |
|
|
ProjectTeam |
Reference to the Registry for all actors that are involved as team members in the current Project. The registry defines the list of Actors, including their roles, that are involved in this project. |
see type |
see type |
n/a |
|
|
ProjectApps |
Reference to the Registry for all applications used within the current Project. The registry defines the list of applications that have been registered. |
see type |
see type |
n/a |
|
OPT |
Classification |
Reference to the access information for classified information. NOTE: not the classified information is referenced, only the unambiguous access to it. |
see type |
see type |
NIL |
|
|
AbsolutePlacement |
Establishment of the World Coordinate System for the Project |
see type |
see type |
0,0,0
and
|
|
|
ProjectMaterials |
Reference to the Registry for all materials used within the current Project. The registry defines the list of materials that have been registered. |
see type |
see type |
n/a |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: The IfcProxy is intended to be a kind of a container for wrapping up non-IFC objects for use within the persistent store. Given that we have only a limited number of constructs formally defined within IFC (and will never be able to define them all), we must provide a mechanism for capturing constructs (primarily geometric) that are not defined by IFC. These constructs may or may not have semantic meaning, depending on whether any shape representations or extended property sets are attached to the IfcProxy. Either way, a receiving system only has to ensure that they are maintained as part of the project model. Such a mechanism allows to round trip data that is part of the project but not necessarily part of the IFC model.
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issue I-184 for changes made in IFC Release 1.5.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
ProxyType |
High level (and only) semantic meaning attached to the IfcProxy, defining the basic construct type behind the Proxy, e.g. Product or Process. |
Product |
Resource |
Product |
|
OPT |
LocalPlacement |
In case of a Product Proxy, the placement within the space of the Project is given. |
see type |
see type |
NIL |
|
OPT |
ProductShape |
Reference to the shape definition of the product. The Product Shape allows for aggregation of Product Component Shapes and therefore for a componentization at the geometric level. It also provides for multiple representations of the Product Shape |
see type |
see type |
NIL |
Formal Propositions:
WR31 |
An IfcProxy shall not be typed, there shall be no Type Definition given. |
WR32 |
An IfcProxy shall have no type driven property sets. |
WR33 |
If the IfcProxy is a Product, then a local placement shall be given, otherwise no local placement shall be given. |
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: The abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among Objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issue I-289 for changes
made in IFC Release 1.5.
See issue I-310 for changes made
in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
OwnerHistory |
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. |
see type |
see type |
n/a |
|
|
ExtendedProperties |
List of references to Property Occurrence Definition that are non type driven. That allows to store attributes of objectified relationships. |
List [0:?] IfcPropertySet |
see type |
see type |
NIL |
|
RelatedIsDependent |
Defines whether both sides of the relationship (relating | related) are equal righted, or whether one depends on the other. TRUE means the related object (see naming convention in subtypes) depends on the relating object, FALSE otherwise. If both RelatingIsDependent and RelatedIsDependent are TRUE, then there is a bi-directional dependency. |
BOOLEAN |
FALSE |
TRUE |
TRUE |
|
RelatingIsDependent |
Defines whether both sides of the relationship (relating | related) are equal righted, or whether one depends on the other. TRUE means the relating object (see naming convention in subtypes) depends on the related object, FALSE otherwise. |
BOOLEAN |
FALSE |
TRUE |
FALSE |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition, since type driven attributes are not foreseen for objectified relationships.
EXPRESS Definition
Definition from IAI: This objectified relationship handles the general concept of containment, that can be either realized by reference or by value. Currently the concept of containment is used for buildings as a special kind of AEC/FM products.
A distinctions is made between the containment and the reference of Elements. A containment relationship shall lead to a hierarchical relationship, i.e. each element can only be contained by one instance of a element container (i.e. site, building, building storey or space). It might however be referenced by many element containers. A multi-storey space is contained (or belongs to) the building storey at which its ground level is, but it is referenced by all the other building storeys, in which it spans. A lift shaft might be contained by the basement, but referenced by all storeys, through which it spans.
NOTE: This is a new entity in IFC Release 1.5.
ISSUE: See issues GI-008, I-116
for changes made in IFC Release 1.5.
See issue I-310 for changes made
in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingObject |
Reference to the container object |
see type |
see type |
n/a |
|
|
RelatedObjects |
Reference to the contained objects |
List [1:?] IfcObject |
see type |
see type |
n/a |
|
RelationshipType |
Defines the type of relationship from the relating side, i.e. following the container object, in which the other objects are contained. |
Project Container |
Space Container |
Project Container |
|
|
ContainedOrReferenced |
Defines whether the relationship is a hierarchical containment relationship (TRUE) or a reference relationship (FALSE) |
BOOLEAN |
FALSE |
TRUE |
TRUE |
Formal Propositions:
WR31 |
The instance to which the RelatingObject relation points (container) shall not be contained in the List of RelatedObjects. |
This class is not typed -- there is no type definition, since type driven attributes are not foreseen for objectified relationships.
EXPRESS Definition
Definition from IAI: This objectified relationship handles the assignment of group members to group objects. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type IfcGroup.
NOTE: This is a new entity in IFC Release 1.5
ISSUE: See issue I-310 for changes made in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingGroup |
Reference to group that finally contains all assigned group members. |
see type |
see type |
n/a |
|
|
RelatedObjects |
References to Objects that will be contained in the group. |
List [1:?] IfcObject |
see type |
see type |
n/a |
Formal Propositions:
WR31 |
The instance to with the relation points shall not be contained in the List of RelatedObjects. |
WR32 |
The dependency flags shall be set so that the RelatedObjects always depend on the RelatingObject (the group) |
Informal Propositions:
IR1 |
The IfcRelGroups relationship shall be defined acyclic. |
This class is not typed -- there is no type definition, since type driven attributes are not foreseen for objectified relationships.
EXPRESS Definition
Definition from IAI: The nesting relationship defines the general concept of elements being nested, so that the nest is of the same type (or supertype) as the nested elements. An example is, that a cost element is a nest of other cost elements. The nesting relationship can be applied in a recursive manner.
NOTE: This is a new entity in IFC Release 1.5.1
ISSUE: See issue I-310 for changes made in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingObject |
The object that represents the nest. |
see type |
see type |
n/a |
|
|
RelatedObjects |
The objects being nested. |
List [1:?] IfcObject |
see type |
see type |
n/a |
Formal Propositions:
WR31 |
The instance to which the relation RelatingObject points shall not be contained in the List of RelatedObjects. |
WR32 |
The type of the RelatingObject shall always be included in the type of each RelatedObject, i.e. the RelatingObject is of the same type of a common supertype |
WR33 |
The dependency flags shall be set so that the RelatedObjects always depends on the RelatingObject (the nest) |
WR34 |
Products shall not be nested (use aggregation relationships). |
Informal Propositions:
IR1 |
The IfcRelNests relationship shall be defined acyclic. |
This class is not typed -- there is no type definition, since type driven attributes are not foreseen for objectified relationships.
EXPRESS Definition
Definition from IAI: This objectified relationship handles the assignment of Products as input or output of Processes.
NOTE: This was a new entity named IfcRelUsesProducts in IFC Release 1.5
ISSUE: See issue I-310 for changes made in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingProcess |
Reference to Process, that handles the Products as input or output. |
see type |
see type |
n/a |
|
|
RelatedProducts |
References to Products, that are either inputs or outputs to the Process |
List [1:?] IfcProduct |
see type |
see type |
n/a |
|
InOrOut |
Flag that indicates whether the Products are inputs into the Process or outputs of the Process, TRUE is input, FALSE is output |
LOGICAL |
FALSE |
TRUE |
TRUE |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition, since type driven attributes are not foreseen for objectified relationships.
EXPRESS Definition
Definition from IAI: This objectified relationship handles the concatenation of processes over time. The Sequence is defined as relationship between two processes. The related object is the successor of the relating object, being the predecessor. A time lag is assigned to a sequence, and the sequence type defines the way in which the time lag applies to the sequence.
IfcRelSequence is defined as an one-to-one relationship, therefore it assigns one predecessor to one successor. However, each IfcProcess can have multiple predecessors and successors, the sequence relationship is truly N-to-M. Many instances of IfcRelSequence have to be created in order to cope with that.
NOTE: This is a new entity in IFC Release 1.5.
ISSUE: See issues I-093, I-200 for
changes made in IFC Release 1.5.
See issue I-310 for changes made
in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingProcess |
Reference to the Process, that is the predecessor. |
see type |
see type |
n/a |
|
|
RelatedProcess |
Reference to the Process, that is the successor. |
see type |
see type |
n/a |
|
|
TimeLag |
Time Duration of the sequence, it is the time lag between the predecessor and the successor as specified by the SequenceType. |
see type |
see type |
n/a |
|
|
SequenceType |
The way in which the time lag applies to the sequence |
Start_Start |
Finish_Finish |
Finish_Start |
Formal Propositions:
WR31 |
The RelatingProcess shall not point to the same instance as the RelatedProcess. |
No Generic Types defined, since type driven attributes are not foreseen for relationships.
EXPRESS Definition
Definition from IAI: This objectified relationship defines the usage relationship of a resource to a process. IfcRelUsesResource is defined as an one-to-one relationship, therefore it assigns one resource to one process. However, each IfcResource can be used in multiple processes, as well as each IfcProcess can use multiple resources; therefore the relationship is truly N-to-M. Many instances of IfcRelUsesResource have to be created in order to cope with that.
NOTE: This was a new entity named IfcRelResourceUse in IFC Release 1.5
ISSUE: See issues I-131, I-201 for
changes made in IFC Release 1.5.1.
See issue I-310 for changes made
in IFC Release 1.5.1.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
RelatingProcess |
Reference to a Process that is resourced by the objectified relationship. |
see type |
see type |
n/a |
|
|
RelatedResource |
Reference to a Resource that is used by the objectified relationship. |
see type |
see type |
n/a |
|
|
ResourceDuration |
The duration for which the resource is required. |
see type |
see type |
n/a |
|
|
ResourceQuantity |
The quantity of a given resource which is available or required. |
Real |
see type |
see type |
1. |
OPT |
ResourceUseCost |
The cost of the resource use in the process |
see type |
see type |
NIL |
No Formal Propositions defined at this level.
This class is not typed -- there is no type definition.
EXPRESS Definition
Definition from IAI: The IfcResource represents a type of substances needed to aid in the process of building construction. Currently, IfcResource doesn’t represent the occurrences of things but their types. A Resource may be considered to be type of labor, equipment or material that assist in the process of building construction but that is not embodied in the final product. That is, its use is temporary. The use of a construction aid may be limited to one process or for processes relating to one product or they may encompass many processes undertaken on many products.
What constitutes a Resource may vary between different stages in a project lifecycle. For instance, during the design stage, computer software may be considered to be an aid to design. Its use may be limited and there may be a particular cost associated with its use on a particular project. During the construction stage, physical construction aids such as cranes, diggers, screwing machines etc. may be considered.
The IfcResource is defined in the Kernel but will be reused and specialized in other schemas.
NOTE: This class carries the semantics of IFC Release 1.0 class IfcResourceObject. In this version, the situation of products being used as resources are not handled. This feature will be provided in R2.0.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
GenericType |
Predefined generic types are specified in an enumeration. A Property Type Definition is available for each generic type . |
Labor |
Material |
Material |
|
OPT |
Descriptor |
Semantic description of the Resource |
STRING |
see type |
see type |
NIL |
OPT |
UnitCost |
Reference to the cost definition of the resource. |
see type |
see type |
NIL |
|
INV |
UsedInProcesses |
Reference to processes, where the resource is used |
Set [0:?] IfcRelUsesResource |
see type |
see type |
NIL |
No formal Propositions are defined at this level.
Generic Type |
Specific Type |
Shared Attributes |
Occurrence Attributes |
Parent Type |
|
|
|
Labor |
|
|
|
Equipment |
|
|
|
Material |
|
|
EXPRESS Definition
Definition from IAI: Most abstract and root class for all IFC Constructs that roots in the IfcKernel or subsequent levels. It handles the ID, ownership and optional a limited history of those objects.
NOTE: This is a new entity in IFC Release 1.5.
ISSUE: See issue I-082 for changes made in IFC Release 1.5.
Attributes and Relationships:
|
Attribute / Relation |
Definition |
Data or Relation Type |
Min |
Max |
Default |
|
ProjectId |
Assignment of a globally unique identifier within the entire software wolrd. |
see type |
see type |
n/a |
Formal Propositions:
UR1 |
ProjectId shall be unique for each instance of all IfcRoot subtypes. |
This class is not typed -- there is no type definition.