Lofting crash

[Anonymous]

Hi, for a school project we are designing and creating an airplane and we are now at the horizontal stabilisers. We have chosen an airfoil and wing shape and I just need to create a loft between two faces with a kind of ellipe-like curve like in the 'Horizontal Stabiliser Design' attachment, which can be done by selecting direction instead of connected at one of the profiles. However Fusion 360 keeps crashing. It's not my CPU or other components as their maximum usage is 60%. Could anyone help me out? The to be lofted design is also attached. Many thanks are due.

[davebYYPCU]

@Anonymous

I have taken a good look at these two designs, and yes the loft crashes, at first I thought I knew why, 

I decided to use your data in a clean file here, and I am hanging on solid and even Patch Lofts, as well.

where did the airfoil come from, the curves are not showing as arcs, or splines, so the source of the airfoil will be the problem.

In all likelihood you are the compounding the problem with one sketch for both profiles.  Loft profiles (and Rails ) should be in independent sketches, from my experience.

@Anonymous or @innovatenate, can you point this set of files to the Lofting gurus, my file has separate sketches still fails.

I can repeat hangs here with separate copies of the original sketch profile, in both Solid and Patch lofts, the hang commences after selecting the second profile, and no preview arrives.

(To be honest I am not waiting for much longer that it should take. Blue Circle and black browser panel arrives)

Thanks in advance....

[TrippyLighting]

Of course the profiles are the problem. Each profile is imported geometry and is comprised of several individual curves, which show curvature discontinuity. Not good!
Then both curves are part of the same sketch. Not good either.

Doing just a straight loft, not touching the distance setting I got as far as the preview after quite a while. After accepting with OK Fusion again took ages to not complete the loft. I didn't not see a warning message, but t did not crash either.

[Anonymous]

Thank you both for your input. These airfoils were created using JavaFoil and then converting them to .svg using photoshop and inkscape. The wings do require this exact airfoil. I can try smoothing the curvature more using photoshop to see if that helps.

[TrippyLighting]

Before resorting to go through the same preocess, which is likely to result in the same loft problem in Fusion 360, can you explain your process, so we might be able to trim out the unnecessary bits with the intention to create proper, native splines in Fusion 360 ?

[Anonymous]

Funny thing is, I did succesfully create a loft using the same airfoils but with different dimensions. I don't understand what is different.

As far as my process goes: I started off with a screenshot from the JavaFoil design which I imported into photoshop. Here I created a single line image from the screenshot which in turn I imported into Inkscape. I used the trace bitmap option which gave me an outer and an inner line as the line created in photoshop was quite wide and I exported this to .svg. In Fusion I imported this svg file and scaled it to the required size. I deleted the outer line as the inner one had the most accurate shape.

[Anonymous]

Please see my other reply

[davebYYPCU]

there has been some water under the bridge now, 

I was able to Sweep with guide rails your design, being the same airfoil will work, but as @TrippyLighting says native Fusion curves are better.

Thanks Trippy, I looked at the comb one at a time, and not together.

[davebYYPCU]

Using the data points in your airfoil, making fusion splines with them in new sketches, no more crashes, and success with the loft now.

Might help....

[TrippyLighting]

Curvature continuity is quite sensitive to minute movements of spline control points. Thus a loft that success in one scenario might fail in another.

my suggestion would be to manually trace these curves with Fusion 360 splines using as few control points as you can get away with and using the tangent handles to further control the shape.

This is tedious work.

[PaulMunford]

Could you put your screen shot straight into Fusion as a background canvas, and then trace over it with Spline curves?

This would save a bit of time, and monkeying around?

Alternatively, could you use an aerofoil generator and then import the points a spline?

http://airfoiltools.com/airfoil/naca4digit

https://knowledge.autodesk.com/support/fusion-360/learn-explore/caas/screencast/Main/Details/84280b4...

[Anonymous]

Thanks everybody for their help. In the end I solved the issue by importing the photoshopped image into inkscape again and tracing the bitmap with a threshold of 1,000. This gave me a .svg image with 4 outer lines, of which I deleted the outer 3. Now, lofting went as smooth as can be.

[jeff_strater]

This is not a crash, as near as I can tell.  I tried the designs, and can create the Loft.  You just have to be VERY patient - it takes a very long time to compute these lofts, probably because of the imported geometry, as @TrippyLighting says.  It looks like @Anonymous was able to successfully find a way to create the model, which is good to hear.

Jeff