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Autodesk / revit-ifc

IFC for Revit and Navisworks (2019+)
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SlabBaseQuantities - NetArea #227

Open yarph opened 4 years ago

yarph commented 4 years ago

The net area shows the surface area of the slab. It should be the gross area minus openings. The englisch description of this property does not explicitly state this, it seems clear that it should be related to gross area. The german description is less ambiguous: "Fläche der Decke (Ansichtsfläche, nicht projizierte oder Mantelfläche). Alle Öffnungen werden abgezogen. Der Wert wird nur angegeben, wenn die Decke eine kostante Dicke hat."

Greetings, Thomas

AngelVelezSosa commented 4 years ago

Can you bring this up in forums.buildingsmart.org to clarify the documentation for quantities? There are several ambiguous items.

yarph commented 4 years ago

Maybe the english versionn isn't so ambiguous after all. It states "Total area of the extruded area of the slab. Openings and recesses are taken into account by subtraction, projections by addition. Only given, if the slab is prismatic."

So not area of the slab, area of the extruded area (so 2 dimensional). Also fits the prismatic condition. In addition the surface area can easily be calculated given the proper net area, the perimeter and the width.