How to *Shell* a complex surface body?

[johngrant2]

Hi, I've just been learning F360 the past month or so and have been working on this for a while. I'm basically trying to make a sculpted veil meant for a 3D wearable project. I've mostly managed to figure out how to get things done so far but I've been stuck here for a week and know I have no clue how to move forward. I managed to get the shell command to work as I wished when I created it as a solid body (img attached) but as a more 3d surface that seems to be impossible no matter how I slice it. I.E. creating a smaller body to use as a cutting tool doesn't work, and extruding the faces fails as well. Any tips on what else to try would be appreciated. 

[TheCADWhisperer]

Some of your splines looked a little "rough" to me on tangency and symmetry.

[johngrant2]

I think I saw that there was the slight symmetry issue on the front in blender just a while ago, but I didn't see the weird tangency thing at all. Do you think it would shell properly if fixed?  

[TheCADWhisperer]

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@johngrant2 wrote:

Do you think it would shell properly if fixed?  

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No.

That area would just be a start.

I saw other suspect areas as well.

And I would probably use Surface Thicken as Shell will not return the correct edges. (Material thickness perpendicular to the material face.)

[johngrant2]

Thicken seems to fail, I tried that and it was failing if I tried to do more than two or so faces, and if I thickened the faces independently the curves weren't aligned. Two faces on either side fail because of geometry that would be self-intersecting, so overall I'm not sure if thicken is the right tool for it. 

[TrippyLighting]

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@johngrant2 wrote:

I think I saw that there was the slight symmetry issue on the front in blender just a while ago, but I didn't see the weird tangency thing at all. Do you think it would shell properly if fixed?  

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I think you don't really know what you re looking at because your geometry makes little sense in Blender or in Fusion 360. I am surprised this even converts in Fusion 360. Did you ever look at the geometry in the box-view mod in Fusion 360 (or in Blender)?

 

[johngrant2]

That my geometry makes little sense does little to tell me how I'm to go about creating a shape with this appearance in fusion, I get the impression generating geometric organic shapes may have been easier in a different program. Also, I'm not entirely sure how to enter box view when I'm working with a surface body, the T-spline body was from a previous attempt. I realize now the file's somewhat a mess with the dozen different ways I tried to trick fusion into lofting a 3d spline.

I also think I may have solved my issue to some extent, I wound up just pulling the unclosed surface, i.e. bottomless, into meshmixer, and using its extrude function which worked to an acceptable extent and reduce let me smooth over whatever weirdness I saw. 

[TrippyLighting]

It is hard to analyze a model that does not really have a timeline showing the steps of how it was created. While your design has a timeline, it seems that most sketches are part of a base feature that might have been condensed from a previous design?

It looked to me at first that the geometry visible in the viewport was created by the T-Spline. That T-Spline geometry I was referring to as making no sense. It was clearly created without understanding how Sub-D or T-spline modeling works. So, yes, I would probably create this in Blender as I find it more suitable for this sort of geometry, but even there the t-spline control cage (which can be exported to .obj and imported into Blender) would not create valid geometry.

But let's move on to the actual object in the viewport.

The curved surfaces of the veil already exhibit bad curvature problems, which can be seen when the curvature map analysis tool is used. Then you applied a patch to the curved underside in hopes this would shell, but that also fails, because fo these curvature problems.

It also won't thicken even when that patch is removed.

I'd be happy to suggest a better workflow, but your design was stripped of the timeline at some point and as such, I don't really know where in the process you went wrong.