Open MatthieuPERIN opened 2 years ago
Please clarify why IfcSystem is not being used to group IfcElements? IfcZone is for grouping IfcSpace only, is it not?
IfcSystem is meant to hold functional grouping only if I remember correctly.
The idea of using IfcSpatialZone is to have a spatial representation for the footprints (i.e. the RESERVATION predefined type) that can also be used to group object that share a common space. This object is no longer reserved to group IfsSpace in IFC 4.3, see Spatial Decomposition Documentation for more details.
IfcSpatialZone
is supposed to be part of the spatial structure, so you can use IfcRelAggregates. See e.g. the Spatial Composition template documentation.
Before we start criticizing 😄 , let's just acknowledge that is has not been used a lot yet and therefore I would give it this pass.
Regarding alignment, there is no doubt that it shall be Spatial Containment.
We could consider a Spatial Decomposition
of IfcFacilityPart into IfcFacilityPart
where the below one has the footprint. I am really torn on this. Maybe you can come up with a solid proposal @MatthieuPERIN?
@SergejMuhic I was thinking that IfcRelAggregates
was for decomposition (whole/part) but as IfcSpatialZone
are not a formal spatial decomposition I used IfcRelContainedInSpatialStructure
to place them inside the spatial structure, and reserve IfcRelAggregate
for decomposition of IfcSpatialZone
into smaller IfcSpatialZone
or IfcSpace
.
Do you agree with that idea ?
In this example, a IfcFacilityPart
for the multi tube might be a bit too much fine decomposition (not addressing the possible overlapping when the substructure passes under railway/roads....), this is why a IfcSpatialZone
is better in my opinion: we need a RESERVATION of space to be able to place the tubes/ducts in the final infrastructure. Thus the addition of a geometry to IfcSpatialZone
here is adequate in my opinion as the objectif is to have a spatial reservation = footprint geometry.
Thank for advice about Spatial Containement (IfcRelContainedInSpatialStructure
) :bow:
Well the template does say that IfcSpatialZone
should be part of the spatial structure, so with the current documentation I would see IfcSpatialZone
to be related through IfcRelAggregates
.
How do we place
IfcSpatialZone
within the Spatial structure.Two solutions are in my opinion feasible:
IfcRelContainedInSpatialStructure
with the idea thatIfcSpatialZone
are likeIfcProduct
that need to be contained within the spatial structure. Problem is that it somehow change the meaning of the relation (no schema change needed, it si teh solution as documented in SpatialDecomposition)IfcRelReferencedInSpatialStructure
with the idea thatIfcSpatialZone
are not properly contained in a spatial structure. Problem is that the same relation will be used to link theIfcSpatialZone
to the upper (the spatilastructure) and the lower (the Element attached to the SpatialZone), still no schema change needed...Example provided from [IFC Rail] Urban Railway Story Line cabling below:
Ping @TLiebich, @SergejMuhic and @larswik !