Building information modeling
Building Information Modeling (BIM) is a process for generation and management of physical and functionnal features of places. The main exchange format for BIM is IFC. Other formats, such as Revit allow creation and manipulation of BIM data.
HOOPS Exchange allows you to read BIM data from any IFC file. The BIM API is available from the A3DSDKBim.h header.
Please note that BIM Data are not part of PRC specifications. As such, the only way to serialize them is by using A3DAsmModelFileExportToIfcXMLFile()
.
Accessing the BIM Data
Once a model file is loaded, the entry point for BIM data is located within the instance of A3DAsmModelFileData
:
- Note
- BIM data reading is only available with IFC files and must be toggled on by setting
A3DRWParamsIFCData::m_bReadRelationships
toA3D_TRUE
.
A3DBIMData
is a standard entity type (A3DBIMDataData
/A3DBIMDataGet()
). Within the A3DBIMDataData
structure, all BIM-related types are abstracted away using the A3DBIMRoot
entity. This means any A3DBIM*
entity can be used as an A3DBIMRoot
entity (A3DBIMRootData
/A3DBIMRootGet()
). Specialized data and getters are available according to the type.
Getting BIM relationships
BIM relationships handle the various relationships of objects within a model. The list of all relationships are contained within A3DBIMDataData::m_ppRelationships
, a standard array of A3DBIMRelationship
entities.
To query the actual type of the relationship, use A3DEntityGetType
on the array element. Then, call the specialized data function according to its type. The following example focuses on the Rel Aggregates relationship:
All relationship are represented as pairs of relating and related elements. They either describe one-to-one or one-to-many relationships where the relating element is m_pRelating
and the related elements is an array where size is m_uiRelatedElementSize
and the pointer is m_ppRelatedElements
. Both relating and related entity types depend on the relationship. In the case of a one-to-one relationship, m_uiRelatedElementsSize
is always 1 and m_ppRelatedElements
can be used as a single pointer.
All relationship entities strictly follow the API convention where the data EData
of an entity E
can be retrieved with a call to EGet(const E*, EData*)
.
Rel Aggregates
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelAggregates | kA3DTypeBIMRelAggregates | A3DBIMObjectDefinition | A3DBIMObjectDefinition |
The aggregation is a one-to-many relationship representing a whole/part composition. In this relationship, the related elements is a list of A3DBIMObjectDefinition
entities that makes a whole: the relating element A3DBIMObjectDefinition
.
Rel Connects Path Elements
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelConnectsPathElements | kA3DTypeBIMRelConnectsPathElements | A3DBIMElement | A3DBIMElement |
This one-to-one relationship provides connectivity information between two path-based elements.
Rel Contained in Spatial Structure
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelContainedInSpatialStructure | kA3DTypeBIMRelContainedInSpatialStructure | A3DBIMSpatialStructureElement | A3DBIMProduct |
This relationship description assign elements to specific levels of a segmented spatial project structure. It is a one-to-many relationship.
Specializations of the relating elements are available:
kA3DTypeBIMBuilding
kA3DTypeBIMBuildingStorey
kA3DTypeBIMSpace
kA3DTypeBIMSite
Rel Fills Element
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelFillsElement | kA3DTypeBIMRelFillsElement | A3DBIMOpeningElement | A3DBIMBuildingElement |
This one-to-one relationship describes an opening element (the relating type) and another element that completly or partially fills it.
- Note
- To read opening elements,
A3DRWParamsIFCData::m_bReadOpeningElements
must be set toA3D_TRUE
.
Rel Space Boundary
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelSpaceBoudary | kA3DTypeBIMRelSpaceBoudary | A3DBIMElement | A3DBIMSpace |
This one-to-one relationship describes a space in an element using boundaries. The relating element is the space itself, which is delimited by the related element.
Rel Voids Element
Entity | Entity enumeration type | Relating type | Related type |
---|---|---|---|
A3DBIMRelVoidsElement | kA3DTypeBIMRelVoidsElement | A3DBIMOpeningElement | A3DBIMElement |
- Note
- To read opening elements,
A3DRWParamsIFCData::m_bReadOpeningElements
must be set toA3D_TRUE
.
The rel voids element describes an opening element that created a void in a building element. It is a one-to-one relationship.