Flat Pattern DXF export incorrect

[tiktuk]

The extruded circles in my design are not exported correctly, see screen shots.

The first is the flat pattern (https://a360.co/2LAwGi3), the second is the exported dxf (https://a360.co/35pqb9X).

[tiktuk]

Clarification: Actually the extruded circle is not exported at all, it's the corner arc that's flipped.

[ryan.bales]

This is definitely not right. Its exporting them as ellipses. It looks like a defect but let me double check before logging it. 

[ryan.bales]

So after some digging, i figured it out. The large bend is off which is resulting in a very slight angle and i think that is the cause of them being converted to ellipses. zoom into the bottom and you'll see the surface thats off 

[tiktuk]

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@ryan.bales wrote:

So after some digging, i figured it out. The large bend is off which is resulting in a very slight angle and i think that is the cause of them being converted to ellipses. zoom into the bottom and you'll see the surface thats off

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I don't understand, which circles are converted to ellipses?

And what about the missing ones and the flipped corner arc ☺️ ?

Thanks for taking a look!

[ryan.bales]

It looked like the corner fillets where being exported as arcs. Usually from the flat pattern not being 100% flat so the arc looks elliptical. That would be the flipped ones.

I didn't seem to have missing ones but i'll look again. 

[tiktuk]

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@ryan.bales wrote:

I didn't seem to have missing ones but i'll look again. 

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You might have seen the file when I had set the four larger circles to cut all the way through. I just did that to make them export. (I thought a public link was to a revision but it's to the updated file obviously.)

[tiktuk]

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@ryan.bales wrote:

It looked like the corner fillets where being exported as arcs. Usually from the flat pattern not being 100% flat so the arc looks elliptical. That would be the flipped ones.

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Elliptical or not, they shouldn't be flipped, no..?

[ryan.bales · Accepted solution]

I've been working to wrap my mind around this. I think there are a few things that we should think about differently and one bug like issue.

First lets look at the potential bug - non-thru features are not shown on the flat pattern. For one thing i've never known them to show through and this is the first instance i've seen someone try it - i'm not suggesting they shouldn't be shown only that they aren't.

Second. The method for forming the large radii is likely what is breaking the arc translation in the flat pattern not simply because they are ellipses. I tested using ellipse cuts or sketch corners without issue. 

Fusion is saying the flat pattern isn't flat. Essentially the lower gap is filled but the face is off by 2.892E-04 deg. Minute, but likely the culprit. Should it be so exact in tolerance for angle deviation when creating a flat pattern? maybe? 

Now for the part that took so long. I theorize this is failing because of what sheet metal used to be capable of. So I rebuilt the cover using Bend - which i highly suggest you do as well. This results in no issues exporting and one SINGLE flange rather than extrude join to fill gaps. I cannot repair your model because of that so i had to start over. 

Bend allows for significantly less fiddling in getting it to work. Also as of the December update - bend now allows you to do multiple bends simultaneously. Here is the wrap using two bends, one with an override and the other the spine in one shot. 

Attached is the DXF and the F3D. 

[tiktuk]

Thanks Ryan, that's amazing, much better method. Thanks a lot for your help ☺️ .

(I still hope it'll be possible to get the semi-extruded circles exported too in the future, can see that being needed often.)