dxf export problem

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Czary
Posts: 1
Joined: Mon Oct 01, 2018 2:49 pm

dxf export problem

Postby Czary » Mon Oct 01, 2018 3:38 pm

Hello, I've designed guitar amp chassis using FreeCad. I've designed an rectangle, extruded it and used SheetMetal WB to create exact shape of the chassis. All of the circles and openings were made as Draft WB objects, later transfered to pockets using Part Design WB.
Problem appears after dxf export. When I import or open dxf in other CAD, some of the objects become triangles and polygons instead of circles.
https://drive.google.com/open?id=1WRShj ... rxQbrCGnBu
chassis FC.PNG
Chassis in FreeCad.
chassis FC.PNG (157.76 KiB) Viewed 185 times
unfold drawing.PNG
Unfold in SheetMetal WB.
unfold drawing.PNG (70.77 KiB) Viewed 185 times
dxf.PNG
After dxf export/import.
dxf.PNG (34.75 KiB) Viewed 185 times
So far, I've used workaround to replace manually faulty objects in Libre Cad.

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13528 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 5c3f7bf8ec51e2c7187789f7edba71a7aa82a88b
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: Polish/Poland (pl_PL)
User avatar
NormandC
Posts: 18534
Joined: Sat Feb 06, 2010 9:52 pm
Location: Québec, Canada

Re: dxf export problem

Postby NormandC » Mon Oct 01, 2018 5:11 pm

Hello CZary,

Welcome.

I downloaded and opened your FreeCAD file, and exported the Unfold_Sketch to DXF, see attached. It opens perfectly fine in DraftSight 2018 on Windows 7, and is identical to the original sketch.
Attachments
2018-10-01_13-09-30.png
2018-10-01_13-09-30.png (75.6 KiB) Viewed 174 times
POCKET SOLDANO 25 CHASSIS.dxf
(12.5 KiB) Downloaded 9 times
UR_
Posts: 856
Joined: Tue Jan 03, 2017 8:42 pm

Re: dxf export problem

Postby UR_ » Mon Oct 01, 2018 6:04 pm

Czary wrote:
Mon Oct 01, 2018 3:38 pm
... some of the objects become triangles and polygons instead of circles.
That's because some circles are ellipses.

2018-10-01 19_58_07-FreeCAD 0.18.png
2018-10-01 19_58_07-FreeCAD 0.18.png (7.85 KiB) Viewed 166 times
2018-10-01 19_57_38-FreeCAD 0.18.png
2018-10-01 19_57_38-FreeCAD 0.18.png (7.99 KiB) Viewed 166 times
UR_
Posts: 856
Joined: Tue Jan 03, 2017 8:42 pm

Re: dxf export problem

Postby UR_ » Mon Oct 01, 2018 7:22 pm

If you are happy with these ellipses and are willing to update to latest daily build, there is new dxf exporter showing bsplines instead of polylines.
Export is done with TechDrawWB or by python

Code: Select all

import Import
obj = App.getDocument("pocket_soldano_25_chassis").getObject("Sketch")
Import.writeDXFObject((obj), u"C:/mypath/my_dxf_file.dxf")
Result will be a dxf file using R14 format without bspline substitution

For details please see here: https://forum.freecadweb.org/viewtopic. ... 10#p251549