Try to Flat Pattern a flat object with curved edges, FP not using selected face

[Anonymous]

I have attached two fusion designs to show what I mean. In the design called "Argo NEW FP's", I have done two flat patterns, one (called Shelter) is triangular with curved sides (sketched using the arc tool). This one will not flat pattern the selected face, instead it only flat patterns the side/edge of the object. This is confirmed when I re-import the dxf into a new design (see other design attached for re-imported dxf's) as the dxf is just a long rectangle. However if I instead create a triangle with curved corners and straight sides, Fusion will do a correct flat pattern. However if I then extrude the curved arcs on the sides of the triangle using Join (so it is still all one sheet metal component, now looking like the Shelter component) the original problem comes back!

I commented on another persons post initially (https://forums.autodesk.com/t5/fusion-360-design-validate/sheet-metal-flat-pattern-not-using-selecte...), but I think this is more of a bug rather than a work-flow issue, so I thought I would be best to post it in Support as it's own thread.

This issue has happened several times before in the past, and I tried to work around it by making a dxf from a sketch instead, but we had issues when the dxf was sent to the manufacturer (no idea what program they use to open the dxf's), as the dxf scale would be wrong, and we would get back assembly parts that were around 30% either too small or too big. This never seems to happen if we send them a dxf from flat pattern, so I really need to find a way to correctly flat pattern these components.

[davebYYPCU · Accepted solution]

To make a flat pattern, surely the tool needs a bend to operate with.

however, that you are getting a flat straight sided object to a flat pattern, means the tool has found an edge to pick up on, but when you remove the straight sides and make them all curves, I think it is looking for something straight.

What you need is to find out why there are size errors with your manufacturer.

Might help...

[Anonymous · Accepted solution]

Yes this worked, making a 0.1mm straight line section on of one of the curves solved the issue.

Thanks 🙂

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@davebYYPCUwrote:

To make a flat pattern, surely the tool needs a bend to operate with.

however, that you are getting a flat straight sided object to a flat pattern, means the tool has found an edge to pick up on, but when you remove the straight sides and make them all curves, I think it is looking for something straight.

What you need is to find out why there are size errors with your manufacturer.

Might help...

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[Anonymous]

Your suggestion worked, I just made a little 0.1mm section of one of the curves into a straight line (see sketch below), and it then flat patterned properly.

[Anonymous]

I just encountered the same issue.

If they want to improve the flatPattern to handle objects without a single straight edge, the user should at least be told that this is the issue!