Could you include a test-file and the name of the application that saved it?

@Lukas Treyer (cnd). could you check on this?

Patch seems OK, but I don't know this format.

Thanks for adding elevation support. I don't see any problems with this. Please share the DXF file if possible. How big is it when you zip it? You could share it with http://pasteall.org/blend/ if it doesn't exceed 30MB.

.is_closed is not always a property !
in dxfgrabber->dxfentities->polylines (line 353) it is not so is_closed will at least work with it.

Added sample dxf for this on dropbox

As a side note, also found a file with a 0 length vector raising on .angle_signed evaluation. (eg: convert line 160)

I don't know exactly how python behaves if you have a getter property and an attribute with the same name. But I assume the getter property will always be called when you want to access that attribute/property. So yes, setting .is_closed might not fail, but I still think it's better to straightly modify flags, since I *assume* we're always calling the property, when we want to know about the .is_closed property.

To make things clear:

.is_closed is always readable.
.is_closed is only writable on polylines, and polylines dosen't rely on flags (dosent even have a flag property).
.is_closed on other entities is not writable (is a getter only) so we rely on flags.

sorry I somehow was caught in Java-thinking and didn't expect more than one class in a file..

so it's only polylines, lwpolylines and splines having .is_closed attribute/property.

why not doing it like this?

if en_template.dxftype == 'POLYLINE':
    en_template.is_closed = False
else:
    # for lwpolylines and splines
    en_template.flags ^= 1

I am not really caring about style here. We can also use try/except if you think this is better.

Only polyline has a writeable .is_closed, other rely on .flags
so if there is a way to know an entity is a polyline, i think we should avoid try except.

For some obscure reason i'm unable to add another diff (support for Gradians angle types)
So i do add the diff here.
Original dxf file from ADSK Civil 3D 2009

diff --git a/io_import_dxf/dxfimport/do.py b/io_import_dxf/dxfimport/do.py
index 8954ba5..65575c9 100644
--- a/io_import_dxf/dxfimport/do.py
+++ b/io_import_dxf/dxfimport/do.py
@@ -297,10 +297,18 @@ class Do:
             angdir = self.dwg.header.get('$ANGDIR', 0)
         kappa = 0.5522848
 
+        # http://help.autodesk.com/view/ACD/2016/ENU/?guid=GUID-A85E8E67-27CD-4C59-BE61-4DC9FADBE74A
+        # TODO: add support for 1 (dms) and 4 (survey)
         if aunits == 0:
+            # Degree
             s = radians(en.start_angle+angbase)
             e = radians(en.end_angle+angbase)
+        elif aunits == 2:
+            # Gradians
+            s = radians(0.9 * (en.start_angle+angbase))
+            e = radians(0.9 * (en.end_angle+angbase))
         else:
+            # Radians
             s = en.start_angle+angbase
             e = en.end_angle+angbase

Can this Revision be closed now since it is commited? Thanks.

Sure. I don't think I can do this. No such action available.