I work in architecture and we often have to create urban contexts for our projects which involves obtaining a building footprint file and then extruding them by hand.

I have attempted to use QGIS (v3.2.2, macOS) to achieve the goal of generating a DXF file with "solid" extrusions of buildings. My process so far:

  • Import footprint data
  • Add Z values using the elevation attribute associated with features
  • Then process resulting layer with GRASS v.extrude using the approximate height attribute associated with features
  • Use Export Project to DXF to generate the DXF file

When I loaded the DXF into Revit I expected to see "solid" extrusions. By solid I mean, volumes with opaque faces. Instead, I got 3D wireframe representations of the extruded footprint, as illustrated in the following image:

3D wireframe extruded footprints

Is there a way to generate "solid" 3D geometry in QGIS and then export it as DXF preserving the "solidity" of the geometry?

  • I have examined the resulting DXF using Autodesk online viewer (viewer.autodesk.com) and it looks like the model only contains 3D Polylines. I don't know much about DXF file format but I would expect to see 3D Face primitives. Is this even something that can be expected of QCAD? – Tomek Sep 17 '18 at 7:19
  • Having spent some time looking at this I've come to the conclusion that this is not possible to achieve with the QGIS. Nor should I really expect this to be possible out of the box. I have managed to achieve my goal of generating solid geometry by using Dynamo. – Tomek Dec 8 '18 at 8:04

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