Organic sheetmetal - lofted flange

[jgpackerRQ4HX]

Hi  all,

Getting an error "cannot create lofted flange with non planar profiles" in Lofted Flange command in sheetmetal.

I'm trying to make a flat development of a surface. Nearest approximation is fine. I've cut an extended version of the surface with planes on which to sketch multiple tangential arcs to approximate the projected curves. This looks like a bug to me, but whenever I draw too many arcs snapping to the projected curves (3d sketch is turned off), I get the above error. The attached shows a successful sheetmetal loft with a few arcs, but adding any more produces that error. If you try to edit the loft and add that extra arc in Sketch5 you'll see the error.

Any ideas?

Also if there's a better method to do this please let me know!

JP

[Warmingup1953]

Are you aiming to create a flat pattern for Laser Cutting?

[jgpackerRQ4HX]

Ultimately yes. Looking for the best workflow...

[davebYYPCU]

Surface Loft the 2 curves as required.

Save as STL.

Load file into Meshmixer.

Edit > Unwrap the surface.

Export flattened surface, as another STL.

Trace file for CNC format.

Might help…..

[jgpackerRQ4HX]

Thanks Dave, haven't looked at Meshmixer before. Tried your suggestion, a possible workaround for sure.

However, I don't know what meshmixer has done with the original ribbon shape which has some compound curvature, and we've now lost the bend data so it can't be put back in the model for checking etc.

Frustrating as it is almost working with the die-form lofted flange...

[davebYYPCU]

You don't lose the Fusion source data, because you should be exporting.  (new objects)

Meshmixer will flatten the panel, with its own algorithm, so I can't explain it, and not sure what you mean.

Same process per body.

Cut and test it.

Might help....

[jgpackerRQ4HX]

Yep, good workaround. Actually you can do modify>convert mesh - prismatic method. Then you can project the shape.

What I mean is there's no bend data - with sheetmental you can unfold, put holes in or whatever, refold etc.

[jgpackerRQ4HX]

@davebYYPCU gave a nice workaround.
Still this nearly works as a proper sheetmetal solution, and looks like a bug, as it's a bit random, and an erroneous error by the looks.
@TheCADWhisperer, @TrippyLighting any ideas?

[TheCADWhisperer]

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@jgpackerRQ4HX wrote:
@TheCADWhisperer any ideas?

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No history for starting geometry and unresolved issue highlighted in the Timeline.

Unconstrained sketches.

Body15 does not look like anything useful to me.

In Fusion 360 bends must be cylindrical or cone (except for some Lofted Flanges).

My ideas:

1. I would fully define all of my sketches.

2. I would probably model this in Autodesk Inventor Professional rather than in Fusion 360.

3. I would be interested in function and permissible tolerance.

[jgpackerRQ4HX]

Thanks Daug.

The unresolved body is because it's taken from the main design... this is just for testing the method so I'm not worried about unconstrained sketches etc.... unless this could be causing the error??

The attached shows the lofted flange trimmed and successfully flat-patterned.

So this error "cannot create lofted flange with non planar profiles" is the issue. As I understand it all the profiles are indeed planar - they are 2d sketches with tangential arcs. Fusion is mainly succeeding, but trying to add those extra arcs to the selection throws up the error.

Yes I should probably splash out on Inventor! Fusion has been (mainly) superb so far though.

Function - a boat cabin I was asked to design/make - would be in 4mm steel, laser cut. Tolerances pretty broad, +/-2mm or so.