CAD Program

[Jay Kempf]

I'll report back when I have really stressed the Fusion360 surfacing kernel. Heading at it with an open mind.

The tool path stuff has been an eye opener for me. I went from a designer's knowledge of machining to making complex female molds on a large format router in a huge hurry. Now I am burning through relatively complex, multi manual tool change aluminum machining for structural bits and pieces that I have designed. Just keeps getting more useful.

This is why I started looking at the CAD side of Fusion360 because it is parametric with the CAM side. And at full boat pricing it is absolutely amazing. If they had a CFD solution it would be THE only choice. Working on that as well. Also trying to figure out a lathe mill that sorta showed up unannounced and upgrading everything in my shop. And last at the moment; I am also looking at building a meter cube 3D printer for large diameter filament mainly for some tooling I am looking at. The Maker world has really changed the way a prototype shop approaches things.

 

[Jay Kempf]

For anyone wondering if the Fusion 360 surfacing kernel is capable I offer this test I have been playing with. Just a screen grab of the moderately stock rendering overlay on a model with something like 30 features to get to here. Nothing custom. I did download a Selig.dat coordinate to spline plug in that seems to work just as suggested. Very pleased with what I have found so far. This isn't CGI, this is a complete engineering approach model with nailed down lofting and real parametrics. I have broken and fixed it a few times already just to get an idea how robust the kernel is. So far so good. More testing is needed but this is a pretty go show of capability. All of the assembly and drafting stuff is just as solid. It will crash and be frustrating in the wrong hands but that is every single 3D modeler. This is near automotive level of surface control.

 

[davidjgall]

I did download a Selig.dat coordinate to spline plug in that seems to work just as suggested.

I'd appreciate a pointer to that file....

This is near automotive level of surface control.

Hmmm. I don't believe that Fusion 360 can actually achieve the "automotive" level of curvature control. The underlying T-Spline engine is only making degree-3 NURBS surfaces which inevitably leads to surface waviness, especially when interpolating between points on non-smoothed data such as Selig.dat coordinate files.

Single-span surface definition and the abilities to employ and edit higher-degree surfaces are required for automotive quality surfacing, as is a capable surfacing artist who knows why and how to use those tools. For that, Autodesk offers a much higher-end family of products (Autodesk Alias) capable of making true "class-A" surfaces, or one could use Rhino3D. But this is the kind of arcana that only affects the highest of high-end developers; for the rest of us, the NURBS surfaces of Fusion 360 are usually "good enough" (except, perhaps, for imported airfoils) and sanding blocks will take care of the rest.

Nice rendering, though, Jay, and doing it with parametric modeling deserves extra kudos for conquering that challenge. Is that on Mars?

 

[Jay Kempf]

Not from what I have seen so far. Much like NX it has G0, G1, G2 in all the lofting commands. Also has conics, and 3rd and 5th splines with either tangent control by handles or by control frame. The T splines package from what I can tell is not the "underlying" geometry kernel but a completely separate package that you can use to sculpt like in Rhino. I turned that on and made one shape but didn't really use it at all. Might be useful for some sculpted, non-aero stuff. So the rendering I put up is 100% parametric and fully editable based on key sections, that are based on relatively fancy splines. This model has inflection curvature which other packages have trouble with. The curve visualization tools are pretty robust including Gaussian, curvature combs, grids, sections, etc... You would have to see it up close and personal and you might be impressed. But all that is beyond where most people will ever get and is completely unnecessary for hand built things but I got into this because of CNC one off stuff.

It is making way smoother surfaces around especially the nose of a loft like this. The is a huge battle in other packages including the fancy stuff. For some reason this just did it without complaining which is odd and I am looking further into it. Doing a loft to a point with tangencies coming in from all directions normally brings the linear algebra engine to its knees. Been crashing these things for decades now. I am so far impressed. What kills me is that I spent 2+ years using the tool path stuff and didn't bother with the CAD side of the program. It has some quirks like all of them but it is not a toy as I had surmised. I think they are using this thing as a test bed for their high end stuff.

Give it a try before deciding it is not capable. If it isn't capable of parametric lofting it is useless to me. What is pretty impressive is it only crashed on me once and that was me not it. Been making changes to see how capable it updates complicated stuff. I am not really seeing any anomalies on the imported airfoil either. The one I brought in is LWK 80-150/K25 with cosine distribution.

The plug in drops the airfoil in and has good positioning and scaling parameters that just work. But it only works in Fusion it isn't stand alone.

Airfoil DAT to Spline | Fusion 360 | Autodesk App Store

To create in seconds spline for airfoil from DAT file for further aircraft development.

apps.autodesk.com

 

[stolflite]

is there software one can use to import a drawing and then scale up to its dimension size which can then printed as a template ?

 

[Jay Kempf]

Yes, they call it a canvas. Lots of YT to help. Plant a .JPG or whatever on a plane, scale to whatever suits, make transparent as you need to work over it. Almost every CAD package has that.

 

[stolflite]

thanks

 

[CBHurricane]

I know this is an old thread, but I'd figure I'd ask my question here. I'm looking into cad programs myself as I have no experience with them, does freecad have the required workbenches for aerodynamics and calculating airspeed, stall speed, etc. As well as the structural dynamics of material to calculate fatigue and stress?

 

[rotax618]

In a word NO, it does have an airplane design workbench but I have never investigated it. I use Freecad to design 3D model aircraft, you can import airfoil .DAT files, loft wings, create surfaces, perform FEM analysis. - not bad for free - zilch - have files on your computer, able to export and import in dozens and dozens of CAD and graphics formats, create tool paths for CNC and professional plans in all views for distribution and printing.
I use the Realthunder Development version, this version is currently being merged into the main branch.