Publish IFC using IfcSpatialZone class instance

[davdelven]

I am requesting the ability to instantiate IfcSpatialZone when publishing using the MVD IFC4 Reference View from Graphisoft Archicad.

The IfcSpatialZone class appears in the IFC Schema when setting up Property Mapping in the IFC Translator.

However, there doesn't appear to be a way to generate any geometry and map it to that class using the Type Mapping setting.

According to the buildingSMART International (bSI) Technical Report:

IFC Spatial Zone – Use Cases, Requirements and Implementation

BR-2023-1025-TR

Report

the IfcSpatialZone entity was introduced in the IFC 4 schema as a flexible spatial object to represent non-hierarchical project decomposition under some functional consideration. The official IfcSpatialZone specification (this URL points out to the current MVD IFC 4.0.2.1. Reference View 1.2. implemented within Archicad) can be found on the buildingSMART website. This entity is a cross-domain/discipline one; therefore, it is also for architecture, structure, facilities, or any other type of infrastructure; therefore, it applies to the Archicad use cases, too. 

• Unlike the traditional IfcSpace entity, which represents physically and logically partitioned space, an IfcSpatialZone may overlap and have independent placement and shape representation.

• This allows it to express various functional zones such as thermal, construction, lighting, or usable area zones.

• IfcZone is just an assignment (a collection of IfcSpace objects) but lacks its own geometry, only the addition of Archicad Zones geometry.

The advantage of using IfcSpatialZone is that a geometry can be attached to an independent spatial structure, not following the hierarchy of IfcSite > IfcBuilding > IfcBuildingStorey. There are situations where such spatial structures need to be conveyed, such as safety volumes or urban planning constraints.

The bSI Technical Report also describes five prominent use case clusters for the IfcSpatialZone model-based approach:

• Spatial Coordination / Reservation

• Spatial Definition / Declaration

• Spatial Regulation / Validation

• Spatial Message / Information

• Spatial Boundary for Analysis & Computation
  
  

So, my wish is to be able to instantiate IfcSpatialZone when publishing using the MVD IFC4 Reference View from Graphisoft Archicad.

[stefan]

I wish to add that the PredefinedType for IfcSpatialZone also includes Fire Compartmentation.

Without this, we can only create Fire Compartments as:

• Independent IfcSpace entities (modelled as Archicad Zone or Morph)
• Grouping Archicad Zones into an IfcZone.USERDEFINED with ObjectType FireCompartment

An IfcZone does not contain any geometry (so we need to assume that the grouped spaces provide the geometry, which lacks the gaps in between the spaces (where the walls are).

An IfcSpatialZone can contain its own geometry. Here it would be nice that we can opt to either merge the referenced IfcSpace entities or map a dedicated Archicad object (Zone or Morph) which represents the exact geometry, over which the user has full control.

[davdelven]

Hi @stefan 

The Spatial Regulation / Validation use case cluster is the most appropriate for framing the fire compartment request. This is because this cluster relates to building regulation and spatial constraints compliance. The IfcSpatialZone, as a non-hierarchical class with its own geometry representation, allows for a detailed representation of specific regulations and constraints within the building, providing more accurate and precise information.

The Spatial Regulation / Validation cluster includes:

• Building Codes
• Restrictions
• City Planning Regulations
• Regulation Information Model (RIM)

Using IfcSpatialZone for fire compartments directly addresses the need to comply with building codes and restrictions related to fire safety.

Additionally, the current IfcSpatialZoneTypeEnum defines existing zone types, including FIRESAFETY, which represents a fire safety zone or fire compartment.

But, regarding domain-specific, local, or regional user-defined spatial zone types, the technical report "IFC Spatial Zone Requirements and Implementation" makes the following recommendations:

* The report advises using *Pset_SpatialZoneCommon` to define these types.
* The report also suggests using `IfcClassification` to set any local or regional spatial zone classification.

These recommendations aim to provide a flexible approach to classifying spatial zones, allowing for specific adaptations based on regional or project-specific needs. The report emphasizes the importance of a common understanding of `IfcSpatialZone` to widen practical usage rather than framing a very specific domain requirement.