Exporting sketch with conic curves to .dxf doesn't work

[trmo]

I have made a design in Fusion 360. I want to export the surfaces to .dxf for laser cutting. I've used the conic curve sketch tool quite a lot, but they all turn out wrong when exporting a sketch to dxf.

The exported .dxf looks wrong in both RDCAM (the laser cutting program) and Inkscape.

When creating a conic curve, you do so in four steps, and it seems only the first three steps are exported:

You set a start point (1), then an end point (2), then the point to define the curve (3), then you edit how curvy the curve is (4).

T

The last part where you put the number, e.g. 0.155 from the fourth image, this doesn't seem to be exported correctly.

If export my sketch, I get this result:

Which looks very much like after the 3rd step from above.

I've tried using the Spline sketch tool as well, but that also exports in strange ways.

I have tried using create sketch on a surface to create a new sketch of that surface, and then export this new sketch; that's my usual approach to exporting to laser cut. But apparently, because the surface is originally made from a sketch using conic curves, this new sketch is also exported inheriting the errors.

So, what do I do? 

[masa.minohara]

Hi @trmo,

Thank you for posting in the forum! I'm having difficulty reproducing the issue at the moment. Would you mind sharing a public link to the design with me and attach the exported DXF file here so I can test?

Just to check, did you use "Save as DXF" command in the browser when exporting as DXF?

One more thing, when you open the DXF file in the online viewer here, is the result correct? If this shows correctly, I believe the export is working and there could be an issue with import in the other application.

[trmo]

Hi, thanks for the quick reply!

I've tried the share thing, this is the link:

https://a360.co/2Pcyd1E

It's a very simple design. I have two sketches. One is a box with a conic curve, the other is a box with a spline. Both are imported incorrectly in the other programs. Both sketches are attached.

I'm using the "Save As DXF" like you show in your image.

I tried uploading to the dxf viewer you linked, and it looks fine. So perhaps Fusion stores some extra meta-data, that these other programs are unfamiliar with. Do you have any suggestions as to how to circumvent this? Some other program that can open these dxf'ses correctly? Can I convert the spline/curve to something else? Some kind of simpler, uneditable line? Can I export the sketches as something else somehow? Or open the fusion model in another program, and export from there?

I've spent more than a month drawing the designs, and everything is curvy and bendy, so I'd really prefer not to do them over.

Thanks for you time

[HughesTooling]

@trmo Haven't downloaded your file as the links are a time waster, in future you'll get more help if you export your f3d and attach.

I did a simple test with a conic spline and QCad failed to import correctly. Rhino and NanoCAD opened it correctly, not sure if you can get an export from these you can use. I suspect not as I tried to export from Rhino, and Qcad still read the file incorrectly. I think a lot of the free and low end CAD systems use the same libraries and can't read all types of splines correctly.

Mark

[HughesTooling]

Just tried an export from Rhino using the R12 Natural option and that file opened correctly in QCad.

Mark

[ryan.bales]

Nice, that is sweet it has that option in Rhino! I'd bet if they are exported using Spline to Polyline from Fusion they'd work okay in QCad.

[trmo]

I've done some searching, and found a few options to export the splines as polylines.

There are addins like "Shaper" and "Splines to polylines", and here's a post suggesting another approach by using some software to convert fusion dxf to inkscape svg:

https://forums.autodesk.com/t5/fusion-360-design-validate/export-svg/td-p/5812107?fbclid=IwAR2E0yv_y...

So the splines can be handled, one way or another, but none of the above seems to be able to do anything with the conic curves.

[ryan.bales]

It always depends on the software reading and interpreting the data. If it can't handle splines then its a tough road. But i see the same result. I was hoping it would convert them but i see the same issue.