DWG export - Polyline issue?

Hi there,

I’ve been noticing something for a while, and am finally bringing it up. I get strange behavior when exporting polylines to DWG. Some segments go missing. Anyone notice anything similar?

Here is the before and after:

If I explode the polyline before exporting, everything works fine. All the segments are properly exported.

For reference, here are my settings for the DWG export:

Finally I should note that these polylines are the result of running the “section” command through some surfaces. I don’t know if that is relevant, but ya never know!

Any ideas?

Best regards,


Hi Tom- can you please post a simple Rhino file that shows the problem? I’ll take a look.


Hi Pascal - will do, shortly… I had deleted the offending curves. I just tried doing it again, and the problem has disappeared. Typical!
It has been happening now and then, so the next time it does I’ll save and send. Thanks!

Hi Pascal,

Finally it happened again! Here is a Rhino file with a bunch of lines. In the “Front” viewport I select the lines, do an “Export Selected” as DWG. I don’t get what I expect in Autocad - a bunch of lines are missing. Hopefully this will help!



ForDWGExport.3dm (48.4 KB)
TempExport.dwg (66.8 KB)

Hi Tom - I copied your export scheme for curves - here the re-import was correct and was in Front, not Top - what does the General page on your export scheme look like?


Hi Pascal,

Here are a few more screenshots:

Hi Tom - It looks like the closed curves are not loved - with everything exploded it seems to work going into eDrawings at least… Still poking… @piroshki - try changing the ‘Project’ setting to View and not Cplane. Actually, I started with Default and changed project to View and that works - just changing your scheme does not…
Here’s a scheme I used that seems to work - PG_DefaultTest.ini (962 Bytes)


Hi Pascal - I agree. The fix is to explode everything and then the closed curves export fine…

Hi Pascal - Just following up this thread as I noticed that when I export a polyline to DWG it also has problems, so it isn’t just for closed curves. Not sure what is going on. I can see how perhaps tweaking the settings for the curve export might have an effect, but if it is loosing entire segments of the polyline I would suggest there is something that needs fixing?
As before, if I explode the polyline it works fine - but not something I should need to do?