Trouble with creating a surface from splines (loft)

[Anonymous]

I have a set of splines imported from a CSV file that I would like to make a surface (and then a solid).

At one "end" of the object the splines begin to overlap in the middle, which I suspect causes the trouble.

I keep getting this error: 

Warning: The loft could not be created.
Try changing the inputs, swapping profiles for rails or a centerline, or adjusting the continuity conditions.

Have a look here: https://a360.co/2rX8m3f

How can I make a surface from the visible splines, and then afterwards make it a solid?

[wmhazzard]

There is no model in your link.  Can you attach an f3d file.

The sketch does open if I click on open in fusion. 

[Anonymous]

Thanks for replying. I see that the online viewer doesn't show much.

Here's a file where I've made a surface as far as I can get with the loft. Adding the next profile (spline) fails.

[TrippyLighting]

That isn't a surprise. Way too many profiles with too many spline control points create curvature problems.

[Anonymous]

Thank you, that does make sense... But what do you suggest as a solution? The splines describe the expansion of the profile in equal steps along the surface.

[TrippyLighting]

Before I can suggest a way to model this - there's more than one - I'd like to know what it is you are trying to model ?

How did you get these splines into that form ? That must have taken ages!

Aha, I see, you used a CSV file. How was that created ?

[Anonymous]

It is a profile for a loudspeaker horn.

The csv data is exported from a spreadsheet that can generate the profile with different parameters and I imported the data (xyz coordinates) into Fusion 360 with a multispline import script.

The calculation of the profile begins with a circle with a given diameter (the narrow end) and expands following a hypex function that is superimposed with a horizontal/vertical ratio constraint and some more modifiers to shape the contour.

[TrippyLighting]

I had a suspicion this was the case 😉

I think with the normal tools in Fusion 360 there is a limit what you can do with this data.

If you want to 3D print this it might be easier to convert this dense mesh into .stl format and then thicken it in  Meshmixer.

Is that spreadsheet including your parameters available ?

[Anonymous]

I think you're right about the data not being fit for Fusion 360 tools as it is. It feels like using a screwdriver for nails.

Yes I would like to 3D print small horns and CNC machine larger ones.

You can download the (rather large) spreadsheet here: https://mega.nz/#!sOYlCCKZ!IxxuioNuUnjCOHmbovSP6ZO14mgDbChEg5pak34vMRE

XYZ data (and more) is on the "front_ondes" tab.

Thank you very much for helping! I really appreciate it.

[Anonymous]

It seems my reply didn't get through or got removed...

I thnik you're right about the data not really being fit for Fusion 360 tools. It feels like driving in nails with a screwdriver.

The spreadsheet is here: Excel sheet on MEGA 

The XYZ data (and more) is on the "front_ondes" tab. Note that the sequence is not xyz but xzy.

Thanks for helping! I really appreciate it.

[Anonymous]

It seems my reply gets autodeleted, maybe because of a download link for the spreadsheet. Now I try to attach...

I think you're right about the data not really being fit for Fusion 360 tools. It feels like driving in nails with a screwdriver.

The XYZ data (and more) is on the "front_ondes" tab. Note that the sequence is not xyz but xzy.

Thanks for helping! I really appreciate it.

[Anonymous]

My replies kep getting removed automatically. I have tried to give a download link to the spreadsheet as well as attaching it here... Is there another way?

I think you're right about the data not really being fit for Fusion 360 tools. It feels like driving in nails with a screwdriver.

Thanks for helping! I really appreciate it.

[Anonymous]

It looks like I'm not allowed to reply anymore?

[Anonymous]

OK, now it might work again.

I think you're right about the data not really being fit for Fusion 360 tools. It feels like driving in nails with a screwdriver.

I'va attached the spreadsheet. The XYZ data (and more) is on the "front_ondes" tab. Note that the sequence is not xyz but xzy.

Thanks for helping! I really appreciate it.

[Anonymous]

Sorry about the mess in this thread by now. Eventually all the posts showed up anyway.

Any ideas on how to make a solid based on this data?

[TrippyLighting]

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@Anonymous wrote:

Any ideas on how to make a solid based on this data?

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No, not really. If this could be converted into a more commonly known format, such as .stl or .obj then that would help.

I use another CAD system, which allows to create surfaces based on mathematical formula but Ive not had the time to look that deep into this.

[TrippyLighting · Accepted solution]

I note that you've not answered the question whether you'd want to 3D print the object, or really wha the method of manufacturing is going to be.

After much searching and experimentation I've been able to find a workflow that results in a mesh in Blender.

There it can be thickened (as shown in the screenshot) and then  it could be exported as a .stl and 3D printed.

This workflow does not include Fusion 360 at all 😉

The general idea is to take the point cloud from the .csv file and convert it into a .stl file. Once we have a .stl file we have some options.

I exported the X,Y,Z coordinates as a .csv file from the Excel sheet. This includes commas as the delimiters.

I opened the text file with Sublime Edit and replaced the commas with spaces and saved it with a .xyz extensions. This is a file extension and format, which will be accepted by Meshlab.

In Meshlab I removed duplicate vertices, calculated normals from point sets  and used the "surface reconstruction Ball Pivoting. Meshlab was new to me and it took a bit of experimentation to figure out the best workflow. That left me with this:

I exported the resulting triangulated mesh as a .stl.

This I opened in Blender, added the needed tris to make the upper edge somewhat smooth, aded a couple of modifiers:

That mesh can be thickened in Blender (or Meshmixer) for 3D printing.

[Anonymous]

Thanks a lot! I will try to duplicate your efforts.

My answer to your question regarding 3D printing got lost in the disappearing posts.

I will 3D print small horns and CNC machine larger ones (in sections).