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Autodesk / revit-ifc

IFC for Revit and Navisworks (2019+)
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MaterialLayer from MaterialLayerSet in wrong order for slabs and roofs ? #435

Open CyrilWaechter opened 2 years ago

CyrilWaechter commented 2 years ago

From my understanding from IfcMaterialLayerSet documentation:

As shown in Figure 8.10.3.7.A, each IfcMaterialLayerSet implicitly defines a material layer set base line (MlsBase), to which the start of the first IfcMaterialLayer is aligned. The total thickness of a layer set is calculated from the individual layer thicknesses, the first layer starting from the MlsBase and following layers being placed on top of the previous (no gaps or overlaps).

When no IfcMaterialLayerSetUsage is provided layers should be given from bottom to top (I assume considering the object local z axis).

I exported following simple file (IFC4 DTV) and apparently the roof (IfcSlab 7350 0P8l0PzbPFqho2jum9nDaP) has a local z pointing up but layers are given from top to bottom: image

Sample file: TriangleBEM_R21.zip

CyrilWaechter commented 2 years ago

I actually get the same issue for the IfcSlab 6962 1oR0Qwj8n21eGJGPnHEGet which is using an IfcMaterialLayerSetUsage: image

local z is pointing up, DirectionSense is POSITIVE with a LayerSetDirection driven by AXIS3 (local z) but layers are still given from top to bottom: image

JOuellette-Autodesk commented 2 years ago

Hi @CyrilWaechter... which version of Revit and the open source tools are you using?

CyrilWaechter commented 2 years ago

Hi @JOuellette-Autodesk ,

Lastly tested with:

Sorry for that I have not mentionned it direcly.

JOuellette-Autodesk commented 2 years ago

https://jira.autodesk.com/browse/REVIT-190531