Exporting 3D curves

[omkar.joshiT78SA]

Since Fusion 360 doesn't have a robust way of creating equation driven 3D curves (without using point coordinates etc), I use Spaceclaim for this. Is there any way to export these 3D curves to Fusion 360? I have tried importing in many formats such as stp, iges, DFX, dwg, parasolid, solidworks, CATIA however none of these exports 3D curves. I had some luck with DFX and dwg but they import the 3D curves as 2D curves projected to one of the principal planes. Would be great if there is a way to do this.

[TrippyLighting]

No, but if you can probably create a surface based on that curve in Spaceclaim and then import that surface into Fusion 360.

[omkar.joshiT78SA]

Thanks, currently I am doing a variation of that - I create a sweep on this curve with only one point lying on it (thus creating an edge along the curve) so when I export the solid as stp in Fusion 360, I can select the edge using Project and create a 3D curve. Since at times it takes long to create this sweep I was hoping to avoid it. Hopefully this functionality will be built in the future.

[hamid.sh.]

Have you tried this add-in for creating equation driven curves directly inside Fusion?

[omkar.joshiT78SA]

Yes, however I was disappointed with the resolution of the long curves because the no. of control points are limited.

[hamid.sh.]

Fair enough, number of points in that add-in cannot be controlled.

OK I have another solution for you, but before that are we sure DXF does not work? I just checked with a 3D spline created in another CAD program (CorelCAD) and when I imported it into Fusion it is still a 3D curve. You can see from this screen cast. Is it limited to spline? 🤔 Would like to see your DXF file (mine is attached).

And now a workaround I found assuming you can import 2D projection of your curve (since you mentioned you can, I can't test it because as I said above my import is itself 3D). All you need is to import twice and each time project it on a different plane. Then make a 3rd sketch and use Project / Include > Intersection Curve, select the two projections and you will have a reconstruction of your original curve. It may also produce some additional curves (because of multiple geometrical solutions) but you can delete them afterwards. I've shown the process in this screencast.

Red curve is the result of Intersection Curve and matches exactly with the original curve, except with few additional curves that can be deleted.

One important note: projections must not be self-intersecting; select 2 out of 3 projections that are not self-intersecting. If there isn't you need to divide your curve into segments that produce no self-intersecting projections.

File is attached as well.

[kandennti · Accepted solution]

Hi @omkar.joshiT78SA .

An add-in for importing and exporting 3D curves is available.
Please feel free to use it.

https://github.com/kantoku-code/Fusion360_Curve3D_Doorway 

[omkar.joshiT78SA]

Thanks, I see that you used "Insert DXF" while I originally just opened the DXF file in Fusion 360. However, with both the methods, I still get a flat curve. I have attached the dxf file and an image of how it was done in Spaceclaim and how it looks after importing in F360.  Either I am missing few settings or maybe it is the way how Spaceclaim creates dxf files.

[jeff_strater]

I think this must be the way that Spaceclaim exports DXF.  The DXF format itself supports 3D geometry, and Fusion can import 3D curves using DXF (example attached), but this DXF contains what looks like a 3D curve projected onto a plane.

[omkar.joshiT78SA]

Indeed, the issue appears to be more towards the way Spaceclaim saves the curves in DXF, may be something I can check with ANSYS. Thanks for "Insert DXF" trick, didn't know about this option, nor did I know about any other way to "import" any model other than just opening it. 

[omkar.joshiT78SA]

Thanks, worked flawlessly for me!

[omkar.joshiT78SA]

Is there any limitation on how long the curve can be with this tool? I see that for very long curves, it seems to make it discrete rather than continuous. Is this by design or just the visual artefact?

[hamid.sh.]

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@omkar.joshiT78SA wrote:

Thanks, I see that you used "Insert DXF" while I originally just opened the DXF file in Fusion 360. However, with both the methods, I still get a flat curve. I have attached the dxf file and an image of how it was done in Spaceclaim and how it looks after importing in F360.  Either I am missing few settings or maybe it is the way how Spaceclaim creates dxf files.

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It's now clear that your problem is in Spaceclaim, otherwise if you really can produce 3D DXF file, Fusion opens it as 3D. Your file is 2D, opened in ANY program. And as such, should you figure out how to generate your file in Spaceclaim you won't need either my method nor an add-in. 

Nevertheless, if in Spaceclaim you can only generate 2D DXF files of your curve (in 2 different perpendicular planes), the method I described will work and give you your original curve. From the picture you attached it looks like Spaceclaim makes DXF file from current view, so just look at it from XY and export, then from YZ and export, then use these two 2D curves to make your original curve inside Fusion, as I showed.

[kandennti]

As for the export, it is created using a combination of Fusion360 API features.
This may be a limitation of the CAD kernel.