topic Re: Surface Revolve and loft issues with multi line sketch in Fusion Design, Validate & Document Forum

Surface Revolve and loft issues with multi line sketch

rjohnstonAA — Tue, 24 Oct 2023 16:28:11 GMT

I have a small profile that is projected out onto a new sketch. That creates lots of line segments in the new sketch. When then surface revolting that to make a smooth crescent shape and then surface lofting it the other 50% of the way down it never is possible (this will make more sense in a second).

So I make a body, convert to mesh, fit curves to mesh section, etc etc and get the profile multi line free (that took a couple days to figure out...) but the problem is the same.

I can't loft the attached file down.

It is either straight line (with G0) or G1 and G2 don't work.

I'd appreciate to know how to do this.

Thanks 🙂

Re: Surface Revolve and loft issues with multi line sketch

TheCADWhisperer — Tue, 24 Oct 2023 18:11:50 GMT

@rjohnstonAA

What is the source of the original geometry?

You have way too many nodes and the curves are broken up with tiny segments.

These curves could be created with 6 or so nodes. Fewer is better with splines (use the Handles to control curvature).

Edit: And enable Capture Design History when you start over.

Re: Surface Revolve and loft issues with multi line sketch

rjohnstonAA — Tue, 24 Oct 2023 18:16:36 GMT

It's an airfoil imported in which is why so many nodes. Less would be much better but always end up with them like this...

They can't however be drawn by hand (since they are airfoils) but yes, less would be great. New to Fusion and usually on SW just merge the segments which is what lead me to converting to mesh then the fit curve to to mesh (sketch 2). That at least gets it somewhat there.

This is a huge file, I just extracted this little part out since no matter what it won't converge but wanting to use F360.

From what I read, there are no other ways to trace a curve so not sure what to do in a scenario like this.

Re: Surface Revolve and loft issues with multi line sketch

rjohnstonAA — Tue, 24 Oct 2023 18:17:09 GMT

History is enabled, this is just a tiny little snippet to make the file light.

Re: Surface Revolve and loft issues with multi line sketch

TheCADWhisperer — Tue, 24 Oct 2023 18:27:06 GMT

@rjohnstonAA wrote:

From what I read, there are ~~no other ways to trace a curve~~ so not sure what to do in a scenario like this.

You can start a New Sketch and trace these curves.

Edit: Wait a minute. Your Sketch2 is one curve?

Enable Capture Design History and recreate surface body and Attached revised file here.

Re: Surface Revolve and loft issues with multi line sketch

rjohnstonAA — Tue, 24 Oct 2023 18:26:06 GMT

Ok - but then simply is the idea that less curves, same curvature will let this converge? I think it is a multi-pronged issue no? If that's all it is, ok - lets give it a try.

Too bad the only way is a manual trace. With everything in there, that's a bit antiquated.

Re: Surface Revolve and loft issues with multi line sketch

rjohnstonAA — Tue, 24 Oct 2023 18:36:24 GMT

@TheCADWhisperer Thanks for the idea by the way 🙂

Re: Surface Revolve and loft issues with multi line sketch

wersy — Tue, 24 Oct 2023 20:16:22 GMT

One thing to remember about airfoils is that there must be no overhangs above or below the zero line.

Another annoyance (round tip) occurs when connecting the splines at the trailing edge. This can be avoided by not connecting the line immediately, but in a second step.

Revolve is not the appropriate tool in this case, loft is sufficient.

I quickly created an airfoil with a few points. Besides the outer arc, you need another profile for the loft.