Smooth curve becomes choppy in DXF export

[A_Owens]

I have a curve created using the intersection curve tool of a sheet body into a solid body. I export the resulting curve into a DXF so that I can open it onto a vinyl cutter software to cut out the curve on some film (sort of like a hobby sticker cutter, or a CriCut). The curve creates an enclosed shape that can be extruded in NX, so I know there's nothing inherently broken about the curve.

However, when I import that DXF of the curve into the vinyl cutter software, it is no longer smooth. It has many individual choppy lines that don't connect. The line breaks can only be seen when zoomed in, but they're big enough to confuse the cutter and not make an enclosed shape.

I've already examined the geometry of the sheet body and of the curve to check for smoothness, continuity, etc using the "examine geometry" tool. I've also tried changing the settings of the DXF export from spline, to 2d polyline, and 3d polyline. What else can I do to create a smooth curve?

 

[Toost]

When exporting, there is that setting you mention : export Spline as... A Poly line in Autocad is , I think, a degree 1 spline. ( linear, straight, "line", between the points) or maybe a "train of lines"
I would assume that "spline as spline" would be the best here.
but, Then the next issue is that you are not (?) using an Autodesk software for printing ( ?) And this software might not be able to handle splines at all, and be the one that chops the spline into lines.
NX can handle very complex splines, and also several different mathematical variants of splines. many( most) other systems are more limited in this aspect.
If the curve you are exporting is a "tolerant curve" you might be best off trying to simplify that before the export.
it could be that a conversion from "spline math type A" to "spline math tybe B" is what produces this issue. ( I have seen similar issues before.)
try Extract Curve in NX and toggle the advanced curve fit to Auto fit,
set minimum and maximum degree to 3 ( degree 3 spline should be accepted by , probably, all systems.)
set the maximum segments to maybe 20 ( uncertain depending on the complexity of your splines.
Join curves can probably be left off.

If this still doesn't work, there is a simplify curve function which will approximate, within a tolerance you set any spline into lines and arc segments.
This can probably be used to try find the reason for the problem.

Regards,
Tomas

The more you know about a subject, the more you know how little you know about that subject.

 

[3DDave]

You could look at the DXF to see what is being exported. It's just a text file. That will tell if the export is a bunch of segments or if the vinyl cutting software is doing the chopping.

 

[A_Owens]

Toost, thanks so much for your suggestion. It ended up being more of a limitation on the vinyl cutter's software, but I benefitted greatly from using the Autofit settings you suggested. The limiting of the min and max degrees to 3 was a game changer.