Lofting from intersecting edges

[GeneralFault]

I am using the latest version of Fusion 360 to try to create a wingtip that has a fairly organic shape. I have been attempting various lofting methods with no success. As the wingtip has multiple complex curves, The profiles are at right angles, and there are two intersecting edges.  Honestly as a beginner, I'm not certain that I am even taking the correct approach at this shape, and I could really use some guidance.

[TrippyLighting]

Yes please put this inthe idea station. I've not worked with the curvature combs yet and this woud have been very confusion.

[cekuhnen]

@TrippyLighting already added!

[davebYYPCU]

Another excellent explanation, Michel, 

and Congratulations on the new one, hope all is well there.

I spent all day yesterday working on a cockpit canopy loft, and was before your post and example for going to DM.

Lets say I know about some of Fusion things, DM, Curve Comb, Zebra checking, Break, but making them work for me, I was total newbee. 

I saw somewhere, Loft tutorial?, sketches not constrained can be pulled to shape without edit sketch but lost the reference to that video.

Big thank you for your time effort and teaching methods.

I think your posts in this thread is huge benefit to aviation and maritime projects modelling.

Will send PM.

Browny.

[cekuhnen]

@davebYYPCU if you could provide screenshots of what you have to build we could provide more tips about how to build them,

Loft is loft - thats not hard to learn. The difficult part is the process and workflow in how to build a good vs a bad model.

[TrippyLighting]

Yes, keep it coming! This is all very educational and very appreciated.

[davebYYPCU]

Don't get me wrong, I am progressing, it is more, 

"why didn't I think of that" when Michel mentioned get out if history, until the shapes are tweaked.

and "use the Zebra more" than I do.

Ipad now, will put some files up bit later, learning all the time,

Browny

[cekuhnen]

@davebYYPCU

Hm I like the DM modeling but I am actually not a big fan of it when you need to build something so complex like a plane.

The timeline will serve better I think.

In His video he breaks the sketch apart. You can also make a new sketch, project a different sketch into it, and the break the links and split the sketch lines.

This way you always remain the original sketches.

Also a note about the Zebra it is a nice tool to see if something has issues or if two edges are G0 or G1.

But for more the Zerba is not accurate enough I would say.

So I would always trust curvature combs on a surface more.

For this you can split a face or body and along the split line show the edge curvature comb.

this obviously is best done in timeline/parametric mode.

[davebYYPCU]

Thanks Clasas,

understand that,

but I have lost some data from yesterday, recent outage may be part of that, so not doing much as the moment.

Give them a few hours or so.

Browny

[GeneralFault]

@cekuhen, It's a good idea. However the wing was already built with a straight edge, so I would have to a bit of work (by my beginner standards) to change it. If I ever do this again, I may go with the small "u" trailing edge to avoid the other tricks needed such as splitting the curves and such.

[GeneralFault]

Wow @michallach81, that was a very helpful post with solid detailed explanations. The only question I have (or at least the only question that I can articulate) is, why can the top rear surface be lofted from one edge to another, whereas the bottom required splitting the front edge?

Do you have any good references for understanding G0, G1, G2?  Sounds like understanding these is key to getting solid lofting results.

As for the wing transition, the wing is horizontal. So it appears that having the curve handles (is there a proper name for those?) are constrained as horizontal. The wingtip leading edge curve is constrained to be parallel with the leading edge rail I used on the wing. This seems to make a nice clean transition. as an aside, thanks for the zebra stripes pointer!

[cekuhnen]

@GeneralFault

G0 G1 G2 G3 is easy to explain

Take a look at the image.

each NURBS surface is made out of a grid system and has 4 sides

When end blending between lines or surfaces the,smoothness is defined by how many points of a curve or surface is adjusted to form a smooth transition.

g0 none

g1 one point and thus has a quick change in curvature being visually noticeable and bad

g2 two,points much better

g3 three points very hard and,visually very appealing

l0ok at the image below in how the right curve changes the shape when flowing into,the left cuvre

I hope this helps

[michallach81]

Nice example but if anyone would look for more mathematically correct answer here's Adam O'Hern video, 7 years old vid, but perfect one:

By the way I'm missing Adams surfacing videos, they're no longer available, only few left on a web. Adam with his mate Josh runs EvD Media company. They have design blog solidsmack, they also do design courses cadjunkie. Adam is the best cad tutor I've ever seen. If I know anything about surfacing is because his vids, years back. He don't make Fusion tutorial, but even his Solidworks one are worth watching.

[cekuhnen]

@michallach81 What does nice images mean?

They pretty much hands down visually explain not only what G0 to G3 is but how it influences the curve and surfaces ?!

It is all about highlights stability and for that you need to continue a surface in a very smooth way as best as possible.

So the question is always how to the CV rows of the to match surface flow into the target surface and over what distance.

G1 to G3 highlight and comb example

https://www.youtube.com/watch?v=GSIIU03NGlY

In the end of the video they also more into CV hand adjustment for technical surfacing something however Fusion cannot do.

[cekuhnen]

@GeneralFault

If you have questions left about what and how G0 to G3 (G2 Fusion) works let me know and I will make a video with Alias and Fusion to show you what the software tools are doing to the CV layout of the nurbs surfaces.

It is honestly pretty easy and less abstract as most people think.

EDIT: you know what here it is:

basic curvature comb and curve CVs position

https://drive.google.com/file/d/0Byzv_NlyKp_2T0lDdXZwMzhSZGc/view

G0 to G3 for surfacing

https://drive.google.com/file/d/0Byzv_NlyKp_2dmpOWVNhSFhMTnM/view

[cekuhnen]

@GeneralFault

This is also a pretty good example to show how Class A surfacing works and how hard or labor intensive it is.

https://www.youtube.com/watch?v=CwPNWjeQJXE

I know how to do this but it is really not a joy plus this defeats the idea of quickly doing design changes as this is so fragile to adjust

[cferguson4DPQJ]

I am not having an easy time with this. Anyone willing to jump in my project and see if they can do it?

[davebYYPCU]

Yep, Export the file for us, 

File > Export, to your hard drive, 

attach like email in the Attachments section under the page here.

Easiest way for us to receive the access.

that said, will be two lofts in the patch environment, 

We may need more profiles to round it out, Loft at the moment likes to shrink wrap the surfaces over the construction, but will check and see first.

[cferguson4DPQJ]

Since this version I have discovered it may be an issue with my planes that I used to construct my sketches. I'm trying a different approach at the planes.

[cferguson4DPQJ]

I am so close....

[cferguson4DPQJ]

Alright. Definitely getting somewhere. The middle and rear section are perfect. now its the front part that i am having issue with. It has some bulging that I am not sure how to get rid of. I don't have tangent as a option when I loft it.

Edit: its been a while since I've used forums, forgive me for not editing my last post.