I received two .dxf for my project that represent my area of interest: one of them contains buildings, the other one terrain elevation (they both are 3D). I can successfully convert them to shapefiles using the Dxf2Shp plugin. They also display nicely compare to sample below:

sample of my model area

However, I loose the height information if I do so. The only field I get in the attribute table is "myid", that simply counts the polygons. Is there a way to convert the files to .shp creating a height field in the attribute tables, that takes the z values from the .dxf? This would already be fine, as the projection is metric.

  • In my experience it could be real tricky to get elevation data out from CAD. My solution is to convert contours (or other data) to a DEM in CAD and then export it to a GeoTiff. See this question for tips on that process. – Martin Dec 6 '13 at 8:59
  • The problem with that would be, that I don have AutoCAD. I only have QGIS… – dom Dec 6 '13 at 9:01

You can try the GRASS command v.in.dxf in Processing or in the Grass plugin (look at GRASS GIS: import DXF).

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Some results in GRASS GIS with 3D dxf files:

  • from Vector support in GRASS GIS: Möbius strip visualization to show the 3D vector capabilities of GRASS 6 - imported from 3D DXF (screenshot: M. Neteler)

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The problem is that there is no support for 3D in QGIS: you must use Python with a module that support 3D (ogr or shapely), look at QGIS user: Using/visualizing 3D data (Z values) and QGIS user: visualizing 3D data (Z values) or data with z attribute: a solution or use the commands of GRASS GIS.

  • I was not totally successful by now, but I think the supposed method will work. I have to learn working with GRASS GIS now. I only used it as a plugin for QGIS in the past, but it seems to provide some functions qGIS can't offer. Thanks! – dom Dec 9 '13 at 16:30

Since 2.14 Qgis supports 3d features. After importing DXF you can add height field with field calculator using expression:




to get Well-Known Text (WKT) representation of the geometry.

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