Why are the circles in my .DXF file imported as "Control Point Splines" and not circles?

[traditional.builds]

So I am creating a file in Adobe Illustrator an saving as a DXF and importing into Fusion 360. I have been troubleshooting this process for a while now and I am running into some more small issues, wondering if anyone knows how to "fix" this.

After importing the .DXF file from Adobe Illustrator, the circles in my sketch are imported as "control point splines". I believe Fusion is doing this because it doesn't "know" that the circles are circles and just reads them as lines. In fact every single line in my sketch is a control point spline.

This is not really a big deal but it becomes tricky when I try to measure parts of the sketch, like the diameter and radius of the circles. But since Fusion is reading them as control point splines, it only gives me the length of the line and not the diameter/radius. 

Wondering if there is a work-around, or another way of importing my sketches that makes editing and measuring them in Fusion 360 easier.

Thank you in advance for all the help recently,

Mike

[MRWakefield]

I suspect that it's Illustrator that's exporting the circles as splines rather than F360 converting them from circles.

Can you attach your DXF here for us to have a look at?

[traditional.builds]

Sure of course! 

Here is the DXF file. I didn't "fix" the problem, but I found a work-around. The design consists of 3 rings which make up the body of a coin/token. On each side of the coin I have a simple design that I extrude into the coin, almost like and engraving.

What I did was I just made sure I had the measurements of the circles from the Illustrator sketch, imported the DXF into Fusion, and re-drew the 3 circles in Fusion instead of using the ones from the DXF. It worked, but I feel like it could be a simpler process haha.

I have also tried a few runs using SVG but I have not found a workflow that "works" for me.

Thanks again for the help,

Mike

[traditional.builds]

This is the result of the coin after mirroring the extrude operation and adding a circular pattern on the edge of the coin to give it groves a real coin might have.

[MRWakefield · Accepted solution]

I checked your DXF in another application and they definitely came through a circles so I double-checked by opening it up in a text editor. This confirmed that Illustrator is exporting them as circles. Then I imported the DXF into Fusion and it too brought them in as circles, so I don't know what I'm doing differently. I'm using the 'Insert | DXF' from the main toolbar. Is this how you're doing it?

[TheCADWhisperer · Accepted solution]

Do not trim these in Illustrator.

Retain them as full circles.

They can then easily be trimmed in Fusion (actually, not even necessary to trim).

If you trim them they become splines.

Also, I would work at the Origin if possible.

[traditional.builds]

Thank you for the reply. I understand what you are doing with the circles now and I will try that out. I can see how that would help Fusion read the circles if they are not trimmed.

[traditional.builds]

Hmm that is odd. I am not sure where our workflow difference is. I have found another way to import the files the way that I like, although I am now running into a new set of problems: some of the DXF sketches I insert are not considered "closed". I notice this when trying to extrude certain parts of the sketch but it does not allow me to select the said shapes, it happens particularly frequently with small or more complex shapes, but I am confused as to where this "opening" is and why, if it is clearly closed in Illustrator, but then tells me it is not in Fusion.

I posted a new forum question for this issue here if you want to check it out: DXF sketches are not closed

Thank you for your help,

Mike

[MRWakefield]

Yes it's very odd. I'm not aware of any Fusion settings that might cause your issues so I'm a bit stumped!

[HughesTooling]

@traditional.builds  I answered in your new post about the gap that's not actually a gap but a bad spline. 

About the circle problem, if I open your file in Rhino you can see the circles are splines so again Fusion is reading the information in the DXF correctly, illustrator is just not exporting circles when it could. Don't know if there's a setting in illustrator for this.

[MRWakefield]

That's strange, as I said in my earlier post, I've imported into an ACAD clone, Notepad++ and Fusion and they all confirm these have been exported as circles.

Here's an extract from the DXF:

AcDbCircle
 10
319.4545897638864
 20
-196.4798888668956
 30
0.0
 40
57.50001524441811

This clearly shows it's a circle so I don't know what's going on here.

[HughesTooling]

I was looking at the DXF in the new thread. You are correct, the file in this thread does have circles and it imports into fusion as circles as well. Sorry for the confusion.

As @TheCADWhisperer states, the trimmed circles are splines though in Fusion and Rhino, so looks like illustrator has a problem with trimmed circles?

[MRWakefield]

No problem, I'm glad we're seeing the same thing. I've no idea why @traditional.builds  gets a different result though.